drm/i915: Add bigjoiner force enable option to debugfs

Commit Message

Shankar, Uma Feb. 12, 2024, 12:50 p.m. UTC

From: Stanislav Lisovskiy <[e-mail]>

For validation purposes, it might be useful to be able to
force Bigjoiner mode, even if current dotclock/resolution
do not require that.
Lets add such to option to debugfs.

v2: - Apparently intel_dp_need_bigjoiner can't be used, when
      debugfs entry is created so lets just check manually
      the DISPLAY_VER.

v3: - Switch to intel_connector from drm_connector(Jani Nikula)
    - Remove redundant modeset lock(Jani Nikula)
    - Use kstrtobool_from_user for boolean value(Jani Nikula)

v4: - Apply the changes to proper function(Jani Nikula)

v5: - Removed unnecessary check from i915_bigjoiner_enable_show
      (Ville Syrjälä)
    - Added eDP connector check to intel_connector_debugfs_add
      (Ville Syrjälä)
    - Removed debug message in order to prevent dmesg flooding
      (Ville Syrjälä)

v6: - Assume now always that m->private is intel_connector
    - Fixed other similar conflicts

v7: - Move bigjoiner force option to intel_connector(Ville Syrjälä)
    - Use DEFINE_SHOW_STORE_ATTRIBUTE instead of defining fops
      manually.(Ville Syrjälä)

v8: - Pass intel_connector to debugfs_create_file, instead of drm_connector.
      (Jani Nikula)

Signed-off-by: Stanislav Lisovskiy <[e-mail]>
---
 .../drm/i915/display/intel_display_debugfs.c  | 47 +++++++++++++++++++
 .../drm/i915/display/intel_display_types.h    |  2 +
 drivers/gpu/drm/i915/display/intel_dp.c       |  4 +-
 3 files changed, 52 insertions(+), 1 deletion(-)

Comments

Jani Nikula Feb. 13, 2024, 9:21 a.m. UTC | #1

On Mon, 12 Feb 2024, Uma Shankar <[e-mail]> wrote:
> From: Stanislav Lisovskiy <[e-mail]>
>
> For validation purposes, it might be useful to be able to
> force Bigjoiner mode, even if current dotclock/resolution
> do not require that.
> Lets add such to option to debugfs.
>
> v2: - Apparently intel_dp_need_bigjoiner can't be used, when
>       debugfs entry is created so lets just check manually
>       the DISPLAY_VER.
>
> v3: - Switch to intel_connector from drm_connector(Jani Nikula)
>     - Remove redundant modeset lock(Jani Nikula)
>     - Use kstrtobool_from_user for boolean value(Jani Nikula)
>
> v4: - Apply the changes to proper function(Jani Nikula)
>
> v5: - Removed unnecessary check from i915_bigjoiner_enable_show
>       (Ville Syrjälä)
>     - Added eDP connector check to intel_connector_debugfs_add
>       (Ville Syrjälä)
>     - Removed debug message in order to prevent dmesg flooding
>       (Ville Syrjälä)
>
> v6: - Assume now always that m->private is intel_connector
>     - Fixed other similar conflicts
>
> v7: - Move bigjoiner force option to intel_connector(Ville Syrjälä)
>     - Use DEFINE_SHOW_STORE_ATTRIBUTE instead of defining fops
>       manually.(Ville Syrjälä)
>
> v8: - Pass intel_connector to debugfs_create_file, instead of drm_connector.
>       (Jani Nikula)
>
> Signed-off-by: Stanislav Lisovskiy <[e-mail]>

Acked-by: Jani Nikula <[e-mail]>


> ---
>  .../drm/i915/display/intel_display_debugfs.c  | 47 +++++++++++++++++++
>  .../drm/i915/display/intel_display_types.h    |  2 +
>  drivers/gpu/drm/i915/display/intel_dp.c       |  4 +-
>  3 files changed, 52 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index 6f2d13c8ccf7..a962b48bcf13 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -1391,6 +1391,20 @@ out:	drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
>  	return ret;
>  }
>  
> +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> +{
> +	struct intel_connector *connector = m->private;
> +	struct drm_crtc *crtc;
> +
> +	crtc = connector->base.state->crtc;
> +	if (connector->base.status != connector_status_connected || !crtc)
> +		return -ENODEV;
> +
> +	seq_printf(m, "Bigjoiner enable: %d\n", connector->force_bigjoiner_enable);
> +
> +	return 0;
> +}
> +
>  static ssize_t i915_dsc_output_format_write(struct file *file,
>  					    const char __user *ubuf,
>  					    size_t len, loff_t *offp)
> @@ -1412,6 +1426,30 @@ static ssize_t i915_dsc_output_format_write(struct file *file,
>  	return len;
>  }
>  
> +static ssize_t i915_bigjoiner_enable_write(struct file *file,
> +					   const char __user *ubuf,
> +					   size_t len, loff_t *offp)
> +{
> +	struct seq_file *m = file->private_data;
> +	struct intel_connector *connector = m->private;
> +	struct drm_crtc *crtc;
> +	bool bigjoiner_en = 0;
> +	int ret;
> +
> +	crtc = connector->base.state->crtc;
> +	if (connector->base.status != connector_status_connected || !crtc)
> +		return -ENODEV;
> +
> +	ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
> +	if (ret < 0)
> +		return ret;
> +
> +	connector->force_bigjoiner_enable = bigjoiner_en;
> +	*offp += len;
> +
> +	return len;
> +}
> +
>  static int i915_dsc_output_format_open(struct inode *inode,
>  				       struct file *file)
>  {
> @@ -1505,6 +1543,8 @@ static const struct file_operations i915_dsc_fractional_bpp_fops = {
>  	.write = i915_dsc_fractional_bpp_write
>  };
>  
> +DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
> +
>  /*
>   * Returns the Current CRTC's bpc.
>   * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> @@ -1586,6 +1626,13 @@ void intel_connector_debugfs_add(struct intel_connector *connector)
>  				    connector, &i915_dsc_fractional_bpp_fops);
>  	}
>  
> +	if (DISPLAY_VER(i915) >= 11 &&
> +	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> +	     connector_type == DRM_MODE_CONNECTOR_eDP)) {
> +		debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
> +				    connector, &i915_bigjoiner_enable_fops);
> +	}
> +
>  	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
>  	    connector_type == DRM_MODE_CONNECTOR_eDP ||
>  	    connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 01eb6e4e6049..0d4012097db1 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -626,6 +626,8 @@ struct intel_connector {
>  
>  	struct intel_dp *mst_port;
>  
> +	bool force_bigjoiner_enable;
> +
>  	struct {
>  		struct drm_dp_aux *dsc_decompression_aux;
>  		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 5045c34a16be..217196196e50 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1205,11 +1205,13 @@ bool intel_dp_need_bigjoiner(struct intel_dp *intel_dp,
>  			     int hdisplay, int clock)
>  {
>  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +	struct intel_connector *connector = intel_dp->attached_connector;
>  
>  	if (!intel_dp_can_bigjoiner(intel_dp))
>  		return false;
>  
> -	return clock > i915->max_dotclk_freq || hdisplay > 5120;
> +	return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
> +	       connector->force_bigjoiner_enable;
>  }
>  
>  static enum drm_mode_status

Rodrigo Vivi Feb. 13, 2024, 2:56 p.m. UTC | #2

On Mon, Feb 12, 2024 at 06:20:11PM +0530, Uma Shankar wrote:
> From: Stanislav Lisovskiy <[e-mail]>
> 
> For validation purposes, it might be useful to be able to
> force Bigjoiner mode, even if current dotclock/resolution
> do not require that.
> Lets add such to option to debugfs.
> 
> v2: - Apparently intel_dp_need_bigjoiner can't be used, when
>       debugfs entry is created so lets just check manually
>       the DISPLAY_VER.
> 
> v3: - Switch to intel_connector from drm_connector(Jani Nikula)
>     - Remove redundant modeset lock(Jani Nikula)
>     - Use kstrtobool_from_user for boolean value(Jani Nikula)
> 
> v4: - Apply the changes to proper function(Jani Nikula)
> 
> v5: - Removed unnecessary check from i915_bigjoiner_enable_show
>       (Ville Syrjälä)
>     - Added eDP connector check to intel_connector_debugfs_add
>       (Ville Syrjälä)
>     - Removed debug message in order to prevent dmesg flooding
>       (Ville Syrjälä)
> 
> v6: - Assume now always that m->private is intel_connector
>     - Fixed other similar conflicts
> 
> v7: - Move bigjoiner force option to intel_connector(Ville Syrjälä)
>     - Use DEFINE_SHOW_STORE_ATTRIBUTE instead of defining fops
>       manually.(Ville Syrjälä)
> 
> v8: - Pass intel_connector to debugfs_create_file, instead of drm_connector.
>       (Jani Nikula)
> 
> Signed-off-by: Stanislav Lisovskiy <[e-mail]>

please remind to sign-off when sending someone else's patch.

> ---
>  .../drm/i915/display/intel_display_debugfs.c  | 47 +++++++++++++++++++
>  .../drm/i915/display/intel_display_types.h    |  2 +
>  drivers/gpu/drm/i915/display/intel_dp.c       |  4 +-
>  3 files changed, 52 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index 6f2d13c8ccf7..a962b48bcf13 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -1391,6 +1391,20 @@ out:	drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
>  	return ret;
>  }
>  
> +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> +{
> +	struct intel_connector *connector = m->private;
> +	struct drm_crtc *crtc;
> +
> +	crtc = connector->base.state->crtc;
> +	if (connector->base.status != connector_status_connected || !crtc)
> +		return -ENODEV;
> +
> +	seq_printf(m, "Bigjoiner enable: %d\n", connector->force_bigjoiner_enable);

probably better with a yes_or_no string?

> +
> +	return 0;
> +}
> +
>  static ssize_t i915_dsc_output_format_write(struct file *file,
>  					    const char __user *ubuf,
>  					    size_t len, loff_t *offp)
> @@ -1412,6 +1426,30 @@ static ssize_t i915_dsc_output_format_write(struct file *file,
>  	return len;
>  }
>  
> +static ssize_t i915_bigjoiner_enable_write(struct file *file,
> +					   const char __user *ubuf,
> +					   size_t len, loff_t *offp)
> +{
> +	struct seq_file *m = file->private_data;
> +	struct intel_connector *connector = m->private;
> +	struct drm_crtc *crtc;
> +	bool bigjoiner_en = 0;
> +	int ret;
> +
> +	crtc = connector->base.state->crtc;
> +	if (connector->base.status != connector_status_connected || !crtc)
> +		return -ENODEV;
> +
> +	ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
> +	if (ret < 0)
> +		return ret;
> +
> +	connector->force_bigjoiner_enable = bigjoiner_en;
> +	*offp += len;
> +
> +	return len;
> +}
> +
>  static int i915_dsc_output_format_open(struct inode *inode,
>  				       struct file *file)
>  {
> @@ -1505,6 +1543,8 @@ static const struct file_operations i915_dsc_fractional_bpp_fops = {
>  	.write = i915_dsc_fractional_bpp_write
>  };
>  
> +DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);

I don't believe this macro here is using the defined _show function,
but maybe I'm not following that very well since this macro is
not widely used.

What about using DEFINE_SIMPLE_ATTRIBUTE instead?

> +
>  /*
>   * Returns the Current CRTC's bpc.
>   * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> @@ -1586,6 +1626,13 @@ void intel_connector_debugfs_add(struct intel_connector *connector)
>  				    connector, &i915_dsc_fractional_bpp_fops);
>  	}
>  
> +	if (DISPLAY_VER(i915) >= 11 &&
> +	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> +	     connector_type == DRM_MODE_CONNECTOR_eDP)) {

I wish we had a simpler check, but I couldn't find. :/

> +		debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
> +				    connector, &i915_bigjoiner_enable_fops);
> +	}
> +
>  	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
>  	    connector_type == DRM_MODE_CONNECTOR_eDP ||
>  	    connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 01eb6e4e6049..0d4012097db1 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -626,6 +626,8 @@ struct intel_connector {
>  
>  	struct intel_dp *mst_port;
>  
> +	bool force_bigjoiner_enable;
> +
>  	struct {
>  		struct drm_dp_aux *dsc_decompression_aux;
>  		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 5045c34a16be..217196196e50 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1205,11 +1205,13 @@ bool intel_dp_need_bigjoiner(struct intel_dp *intel_dp,
>  			     int hdisplay, int clock)
>  {
>  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +	struct intel_connector *connector = intel_dp->attached_connector;
>  
>  	if (!intel_dp_can_bigjoiner(intel_dp))
>  		return false;
>  
> -	return clock > i915->max_dotclk_freq || hdisplay > 5120;
> +	return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
> +	       connector->force_bigjoiner_enable;

I'm just not comfortable with the magic _show of that macro and would
prefer a more simple and straight forward and widely used version.

Other then that everything else looks good to me.

Thanks,
Rodrigo.

>  }
>  
>  static enum drm_mode_status
> -- 
> 2.42.0
>

Shankar, Uma Feb. 13, 2024, 3:11 p.m. UTC | #3

> -----Original Message-----
> From: Rodrigo Vivi <[e-mail]>
> Sent: Tuesday, February 13, 2024 8:26 PM
> To: Shankar, Uma <[e-mail]>
> Cc: [e-mail]; Lisovskiy, Stanislav
> <[e-mail]>; [e-mail];
> [e-mail]
> Subject: Re: [PATCH] drm/i915: Add bigjoiner force enable option to debugfs
> 
> On Mon, Feb 12, 2024 at 06:20:11PM +0530, Uma Shankar wrote:
> > From: Stanislav Lisovskiy <[e-mail]>
> >
> > For validation purposes, it might be useful to be able to force
> > Bigjoiner mode, even if current dotclock/resolution do not require
> > that.
> > Lets add such to option to debugfs.
> >
> > v2: - Apparently intel_dp_need_bigjoiner can't be used, when
> >       debugfs entry is created so lets just check manually
> >       the DISPLAY_VER.
> >
> > v3: - Switch to intel_connector from drm_connector(Jani Nikula)
> >     - Remove redundant modeset lock(Jani Nikula)
> >     - Use kstrtobool_from_user for boolean value(Jani Nikula)
> >
> > v4: - Apply the changes to proper function(Jani Nikula)
> >
> > v5: - Removed unnecessary check from i915_bigjoiner_enable_show
> >       (Ville Syrjälä)
> >     - Added eDP connector check to intel_connector_debugfs_add
> >       (Ville Syrjälä)
> >     - Removed debug message in order to prevent dmesg flooding
> >       (Ville Syrjälä)
> >
> > v6: - Assume now always that m->private is intel_connector
> >     - Fixed other similar conflicts
> >
> > v7: - Move bigjoiner force option to intel_connector(Ville Syrjälä)
> >     - Use DEFINE_SHOW_STORE_ATTRIBUTE instead of defining fops
> >       manually.(Ville Syrjälä)
> >
> > v8: - Pass intel_connector to debugfs_create_file, instead of drm_connector.
> >       (Jani Nikula)
> >
> > Signed-off-by: Stanislav Lisovskiy <[e-mail]>
> 
> please remind to sign-off when sending someone else's patch.

Oh yeah, sorry missed it. Was filling in for Stan while he was OOO.
@Lisovskiy, Stanislav Please address rest of the comments raised by Rodrigo.

Regards,
Uma Shankar

> > ---
> >  .../drm/i915/display/intel_display_debugfs.c  | 47 +++++++++++++++++++
> >  .../drm/i915/display/intel_display_types.h    |  2 +
> >  drivers/gpu/drm/i915/display/intel_dp.c       |  4 +-
> >  3 files changed, 52 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > index 6f2d13c8ccf7..a962b48bcf13 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > @@ -1391,6 +1391,20 @@ out:	drm_modeset_unlock(&i915-
> >drm.mode_config.connection_mutex);
> >  	return ret;
> >  }
> >
> > +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> > +{
> > +	struct intel_connector *connector = m->private;
> > +	struct drm_crtc *crtc;
> > +
> > +	crtc = connector->base.state->crtc;
> > +	if (connector->base.status != connector_status_connected || !crtc)
> > +		return -ENODEV;
> > +
> > +	seq_printf(m, "Bigjoiner enable: %d\n",
> > +connector->force_bigjoiner_enable);
> 
> probably better with a yes_or_no string?
> 
> > +
> > +	return 0;
> > +}
> > +
> >  static ssize_t i915_dsc_output_format_write(struct file *file,
> >  					    const char __user *ubuf,
> >  					    size_t len, loff_t *offp)
> > @@ -1412,6 +1426,30 @@ static ssize_t i915_dsc_output_format_write(struct
> file *file,
> >  	return len;
> >  }
> >
> > +static ssize_t i915_bigjoiner_enable_write(struct file *file,
> > +					   const char __user *ubuf,
> > +					   size_t len, loff_t *offp)
> > +{
> > +	struct seq_file *m = file->private_data;
> > +	struct intel_connector *connector = m->private;
> > +	struct drm_crtc *crtc;
> > +	bool bigjoiner_en = 0;
> > +	int ret;
> > +
> > +	crtc = connector->base.state->crtc;
> > +	if (connector->base.status != connector_status_connected || !crtc)
> > +		return -ENODEV;
> > +
> > +	ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	connector->force_bigjoiner_enable = bigjoiner_en;
> > +	*offp += len;
> > +
> > +	return len;
> > +}
> > +
> >  static int i915_dsc_output_format_open(struct inode *inode,
> >  				       struct file *file)
> >  {
> > @@ -1505,6 +1543,8 @@ static const struct file_operations
> i915_dsc_fractional_bpp_fops = {
> >  	.write = i915_dsc_fractional_bpp_write  };
> >
> > +DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
> 
> I don't believe this macro here is using the defined _show function, but maybe I'm
> not following that very well since this macro is not widely used.
> 
> What about using DEFINE_SIMPLE_ATTRIBUTE instead?
> 
> > +
> >  /*
> >   * Returns the Current CRTC's bpc.
> >   * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> > @@ -1586,6 +1626,13 @@ void intel_connector_debugfs_add(struct
> intel_connector *connector)
> >  				    connector, &i915_dsc_fractional_bpp_fops);
> >  	}
> >
> > +	if (DISPLAY_VER(i915) >= 11 &&
> > +	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > +	     connector_type == DRM_MODE_CONNECTOR_eDP)) {
> 
> I wish we had a simpler check, but I couldn't find. :/
> 
> > +		debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
> > +				    connector, &i915_bigjoiner_enable_fops);
> > +	}
> > +
> >  	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
> >  	    connector_type == DRM_MODE_CONNECTOR_eDP ||
> >  	    connector_type == DRM_MODE_CONNECTOR_DisplayPort || diff --git
> > a/drivers/gpu/drm/i915/display/intel_display_types.h
> > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index 01eb6e4e6049..0d4012097db1 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -626,6 +626,8 @@ struct intel_connector {
> >
> >  	struct intel_dp *mst_port;
> >
> > +	bool force_bigjoiner_enable;
> > +
> >  	struct {
> >  		struct drm_dp_aux *dsc_decompression_aux;
> >  		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 5045c34a16be..217196196e50 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -1205,11 +1205,13 @@ bool intel_dp_need_bigjoiner(struct intel_dp
> *intel_dp,
> >  			     int hdisplay, int clock)
> >  {
> >  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > +	struct intel_connector *connector = intel_dp->attached_connector;
> >
> >  	if (!intel_dp_can_bigjoiner(intel_dp))
> >  		return false;
> >
> > -	return clock > i915->max_dotclk_freq || hdisplay > 5120;
> > +	return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
> > +	       connector->force_bigjoiner_enable;
> 
> I'm just not comfortable with the magic _show of that macro and would prefer a
> more simple and straight forward and widely used version.
> 
> Other then that everything else looks good to me.
> 
> Thanks,
> Rodrigo.
> 
> >  }
> >
> >  static enum drm_mode_status
> > --
> > 2.42.0
> >

Stanislav Lisovskiy Feb. 13, 2024, 3:21 p.m. UTC | #4

On Tue, Feb 13, 2024 at 05:11:37PM +0200, Shankar, Uma wrote:
> 
> 
> > -----Original Message-----
> > From: Rodrigo Vivi <[e-mail]>
> > Sent: Tuesday, February 13, 2024 8:26 PM
> > To: Shankar, Uma <[e-mail]>
> > Cc: [e-mail]; Lisovskiy, Stanislav
> > <[e-mail]>; [e-mail];
> > [e-mail]
> > Subject: Re: [PATCH] drm/i915: Add bigjoiner force enable option to debugfs
> > 
> > On Mon, Feb 12, 2024 at 06:20:11PM +0530, Uma Shankar wrote:
> > > From: Stanislav Lisovskiy <[e-mail]>
> > >
> > > For validation purposes, it might be useful to be able to force
> > > Bigjoiner mode, even if current dotclock/resolution do not require
> > > that.
> > > Lets add such to option to debugfs.
> > >
> > > v2: - Apparently intel_dp_need_bigjoiner can't be used, when
> > >       debugfs entry is created so lets just check manually
> > >       the DISPLAY_VER.
> > >
> > > v3: - Switch to intel_connector from drm_connector(Jani Nikula)
> > >     - Remove redundant modeset lock(Jani Nikula)
> > >     - Use kstrtobool_from_user for boolean value(Jani Nikula)
> > >
> > > v4: - Apply the changes to proper function(Jani Nikula)
> > >
> > > v5: - Removed unnecessary check from i915_bigjoiner_enable_show
> > >       (Ville Syrjälä)
> > >     - Added eDP connector check to intel_connector_debugfs_add
> > >       (Ville Syrjälä)
> > >     - Removed debug message in order to prevent dmesg flooding
> > >       (Ville Syrjälä)
> > >
> > > v6: - Assume now always that m->private is intel_connector
> > >     - Fixed other similar conflicts
> > >
> > > v7: - Move bigjoiner force option to intel_connector(Ville Syrjälä)
> > >     - Use DEFINE_SHOW_STORE_ATTRIBUTE instead of defining fops
> > >       manually.(Ville Syrjälä)
> > >
> > > v8: - Pass intel_connector to debugfs_create_file, instead of drm_connector.
> > >       (Jani Nikula)
> > >
> > > Signed-off-by: Stanislav Lisovskiy <[e-mail]>
> > 
> > please remind to sign-off when sending someone else's patch.
> 
> Oh yeah, sorry missed it. Was filling in for Stan while he was OOO.
> @Lisovskiy, Stanislav Please address rest of the comments raised by Rodrigo.

Sorry, had that pushed already in the morning, since it was Acked and I was asked
to do it asap.

Stan

> 
> Regards,
> Uma Shankar
> 
> > > ---
> > >  .../drm/i915/display/intel_display_debugfs.c  | 47 +++++++++++++++++++
> > >  .../drm/i915/display/intel_display_types.h    |  2 +
> > >  drivers/gpu/drm/i915/display/intel_dp.c       |  4 +-
> > >  3 files changed, 52 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > index 6f2d13c8ccf7..a962b48bcf13 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > @@ -1391,6 +1391,20 @@ out:	drm_modeset_unlock(&i915-
> > >drm.mode_config.connection_mutex);
> > >  	return ret;
> > >  }
> > >
> > > +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> > > +{
> > > +	struct intel_connector *connector = m->private;
> > > +	struct drm_crtc *crtc;
> > > +
> > > +	crtc = connector->base.state->crtc;
> > > +	if (connector->base.status != connector_status_connected || !crtc)
> > > +		return -ENODEV;
> > > +
> > > +	seq_printf(m, "Bigjoiner enable: %d\n",
> > > +connector->force_bigjoiner_enable);
> > 
> > probably better with a yes_or_no string?
> > 
> > > +
> > > +	return 0;
> > > +}
> > > +
> > >  static ssize_t i915_dsc_output_format_write(struct file *file,
> > >  					    const char __user *ubuf,
> > >  					    size_t len, loff_t *offp)
> > > @@ -1412,6 +1426,30 @@ static ssize_t i915_dsc_output_format_write(struct
> > file *file,
> > >  	return len;
> > >  }
> > >
> > > +static ssize_t i915_bigjoiner_enable_write(struct file *file,
> > > +					   const char __user *ubuf,
> > > +					   size_t len, loff_t *offp)
> > > +{
> > > +	struct seq_file *m = file->private_data;
> > > +	struct intel_connector *connector = m->private;
> > > +	struct drm_crtc *crtc;
> > > +	bool bigjoiner_en = 0;
> > > +	int ret;
> > > +
> > > +	crtc = connector->base.state->crtc;
> > > +	if (connector->base.status != connector_status_connected || !crtc)
> > > +		return -ENODEV;
> > > +
> > > +	ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	connector->force_bigjoiner_enable = bigjoiner_en;
> > > +	*offp += len;
> > > +
> > > +	return len;
> > > +}
> > > +
> > >  static int i915_dsc_output_format_open(struct inode *inode,
> > >  				       struct file *file)
> > >  {
> > > @@ -1505,6 +1543,8 @@ static const struct file_operations
> > i915_dsc_fractional_bpp_fops = {
> > >  	.write = i915_dsc_fractional_bpp_write  };
> > >
> > > +DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
> > 
> > I don't believe this macro here is using the defined _show function, but maybe I'm
> > not following that very well since this macro is not widely used.
> > 
> > What about using DEFINE_SIMPLE_ATTRIBUTE instead?
> > 
> > > +
> > >  /*
> > >   * Returns the Current CRTC's bpc.
> > >   * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> > > @@ -1586,6 +1626,13 @@ void intel_connector_debugfs_add(struct
> > intel_connector *connector)
> > >  				    connector, &i915_dsc_fractional_bpp_fops);
> > >  	}
> > >
> > > +	if (DISPLAY_VER(i915) >= 11 &&
> > > +	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > > +	     connector_type == DRM_MODE_CONNECTOR_eDP)) {
> > 
> > I wish we had a simpler check, but I couldn't find. :/
> > 
> > > +		debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
> > > +				    connector, &i915_bigjoiner_enable_fops);
> > > +	}
> > > +
> > >  	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
> > >  	    connector_type == DRM_MODE_CONNECTOR_eDP ||
> > >  	    connector_type == DRM_MODE_CONNECTOR_DisplayPort || diff --git
> > > a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > index 01eb6e4e6049..0d4012097db1 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > @@ -626,6 +626,8 @@ struct intel_connector {
> > >
> > >  	struct intel_dp *mst_port;
> > >
> > > +	bool force_bigjoiner_enable;
> > > +
> > >  	struct {
> > >  		struct drm_dp_aux *dsc_decompression_aux;
> > >  		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
> > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > > b/drivers/gpu/drm/i915/display/intel_dp.c
> > > index 5045c34a16be..217196196e50 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > @@ -1205,11 +1205,13 @@ bool intel_dp_need_bigjoiner(struct intel_dp
> > *intel_dp,
> > >  			     int hdisplay, int clock)
> > >  {
> > >  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > +	struct intel_connector *connector = intel_dp->attached_connector;
> > >
> > >  	if (!intel_dp_can_bigjoiner(intel_dp))
> > >  		return false;
> > >
> > > -	return clock > i915->max_dotclk_freq || hdisplay > 5120;
> > > +	return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
> > > +	       connector->force_bigjoiner_enable;
> > 
> > I'm just not comfortable with the magic _show of that macro and would prefer a
> > more simple and straight forward and widely used version.
> > 
> > Other then that everything else looks good to me.
> > 
> > Thanks,
> > Rodrigo.
> > 
> > >  }
> > >
> > >  static enum drm_mode_status
> > > --
> > > 2.42.0
> > >

Rodrigo Vivi Feb. 13, 2024, 3:33 p.m. UTC | #5

On Tue, Feb 13, 2024 at 05:21:26PM +0200, Lisovskiy, Stanislav wrote:
> On Tue, Feb 13, 2024 at 05:11:37PM +0200, Shankar, Uma wrote:
> > 
> > 
> > > -----Original Message-----
> > > From: Rodrigo Vivi <[e-mail]>
> > > Sent: Tuesday, February 13, 2024 8:26 PM
> > > To: Shankar, Uma <[e-mail]>
> > > Cc: [e-mail]; Lisovskiy, Stanislav
> > > <[e-mail]>; [e-mail];
> > > [e-mail]
> > > Subject: Re: [PATCH] drm/i915: Add bigjoiner force enable option to debugfs
> > > 
> > > On Mon, Feb 12, 2024 at 06:20:11PM +0530, Uma Shankar wrote:
> > > > From: Stanislav Lisovskiy <[e-mail]>
> > > >
> > > > For validation purposes, it might be useful to be able to force
> > > > Bigjoiner mode, even if current dotclock/resolution do not require
> > > > that.
> > > > Lets add such to option to debugfs.
> > > >
> > > > v2: - Apparently intel_dp_need_bigjoiner can't be used, when
> > > >       debugfs entry is created so lets just check manually
> > > >       the DISPLAY_VER.
> > > >
> > > > v3: - Switch to intel_connector from drm_connector(Jani Nikula)
> > > >     - Remove redundant modeset lock(Jani Nikula)
> > > >     - Use kstrtobool_from_user for boolean value(Jani Nikula)
> > > >
> > > > v4: - Apply the changes to proper function(Jani Nikula)
> > > >
> > > > v5: - Removed unnecessary check from i915_bigjoiner_enable_show
> > > >       (Ville Syrjälä)
> > > >     - Added eDP connector check to intel_connector_debugfs_add
> > > >       (Ville Syrjälä)
> > > >     - Removed debug message in order to prevent dmesg flooding
> > > >       (Ville Syrjälä)
> > > >
> > > > v6: - Assume now always that m->private is intel_connector
> > > >     - Fixed other similar conflicts
> > > >
> > > > v7: - Move bigjoiner force option to intel_connector(Ville Syrjälä)
> > > >     - Use DEFINE_SHOW_STORE_ATTRIBUTE instead of defining fops
> > > >       manually.(Ville Syrjälä)
> > > >
> > > > v8: - Pass intel_connector to debugfs_create_file, instead of drm_connector.
> > > >       (Jani Nikula)
> > > >
> > > > Signed-off-by: Stanislav Lisovskiy <[e-mail]>
> > > 
> > > please remind to sign-off when sending someone else's patch.
> > 
> > Oh yeah, sorry missed it. Was filling in for Stan while he was OOO.
> > @Lisovskiy, Stanislav Please address rest of the comments raised by Rodrigo.
> 
> Sorry, had that pushed already in the morning, since it was Acked and I was asked
> to do it asap.

no worries. if you are confident that the _show function magically works I trust
your tests more then my eyes and greps.

> 
> Stan
> 
> > 
> > Regards,
> > Uma Shankar
> > 
> > > > ---
> > > >  .../drm/i915/display/intel_display_debugfs.c  | 47 +++++++++++++++++++
> > > >  .../drm/i915/display/intel_display_types.h    |  2 +
> > > >  drivers/gpu/drm/i915/display/intel_dp.c       |  4 +-
> > > >  3 files changed, 52 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > index 6f2d13c8ccf7..a962b48bcf13 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > @@ -1391,6 +1391,20 @@ out:	drm_modeset_unlock(&i915-
> > > >drm.mode_config.connection_mutex);
> > > >  	return ret;
> > > >  }
> > > >
> > > > +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> > > > +{
> > > > +	struct intel_connector *connector = m->private;
> > > > +	struct drm_crtc *crtc;
> > > > +
> > > > +	crtc = connector->base.state->crtc;
> > > > +	if (connector->base.status != connector_status_connected || !crtc)
> > > > +		return -ENODEV;
> > > > +
> > > > +	seq_printf(m, "Bigjoiner enable: %d\n",
> > > > +connector->force_bigjoiner_enable);
> > > 
> > > probably better with a yes_or_no string?
> > > 
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > >  static ssize_t i915_dsc_output_format_write(struct file *file,
> > > >  					    const char __user *ubuf,
> > > >  					    size_t len, loff_t *offp)
> > > > @@ -1412,6 +1426,30 @@ static ssize_t i915_dsc_output_format_write(struct
> > > file *file,
> > > >  	return len;
> > > >  }
> > > >
> > > > +static ssize_t i915_bigjoiner_enable_write(struct file *file,
> > > > +					   const char __user *ubuf,
> > > > +					   size_t len, loff_t *offp)
> > > > +{
> > > > +	struct seq_file *m = file->private_data;
> > > > +	struct intel_connector *connector = m->private;
> > > > +	struct drm_crtc *crtc;
> > > > +	bool bigjoiner_en = 0;
> > > > +	int ret;
> > > > +
> > > > +	crtc = connector->base.state->crtc;
> > > > +	if (connector->base.status != connector_status_connected || !crtc)
> > > > +		return -ENODEV;
> > > > +
> > > > +	ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
> > > > +	if (ret < 0)
> > > > +		return ret;
> > > > +
> > > > +	connector->force_bigjoiner_enable = bigjoiner_en;
> > > > +	*offp += len;
> > > > +
> > > > +	return len;
> > > > +}
> > > > +
> > > >  static int i915_dsc_output_format_open(struct inode *inode,
> > > >  				       struct file *file)
> > > >  {
> > > > @@ -1505,6 +1543,8 @@ static const struct file_operations
> > > i915_dsc_fractional_bpp_fops = {
> > > >  	.write = i915_dsc_fractional_bpp_write  };
> > > >
> > > > +DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
> > > 
> > > I don't believe this macro here is using the defined _show function, but maybe I'm
> > > not following that very well since this macro is not widely used.
> > > 
> > > What about using DEFINE_SIMPLE_ATTRIBUTE instead?
> > > 
> > > > +
> > > >  /*
> > > >   * Returns the Current CRTC's bpc.
> > > >   * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> > > > @@ -1586,6 +1626,13 @@ void intel_connector_debugfs_add(struct
> > > intel_connector *connector)
> > > >  				    connector, &i915_dsc_fractional_bpp_fops);
> > > >  	}
> > > >
> > > > +	if (DISPLAY_VER(i915) >= 11 &&
> > > > +	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > > > +	     connector_type == DRM_MODE_CONNECTOR_eDP)) {
> > > 
> > > I wish we had a simpler check, but I couldn't find. :/
> > > 
> > > > +		debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
> > > > +				    connector, &i915_bigjoiner_enable_fops);
> > > > +	}
> > > > +
> > > >  	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
> > > >  	    connector_type == DRM_MODE_CONNECTOR_eDP ||
> > > >  	    connector_type == DRM_MODE_CONNECTOR_DisplayPort || diff --git
> > > > a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > index 01eb6e4e6049..0d4012097db1 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > @@ -626,6 +626,8 @@ struct intel_connector {
> > > >
> > > >  	struct intel_dp *mst_port;
> > > >
> > > > +	bool force_bigjoiner_enable;
> > > > +
> > > >  	struct {
> > > >  		struct drm_dp_aux *dsc_decompression_aux;
> > > >  		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > index 5045c34a16be..217196196e50 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > @@ -1205,11 +1205,13 @@ bool intel_dp_need_bigjoiner(struct intel_dp
> > > *intel_dp,
> > > >  			     int hdisplay, int clock)
> > > >  {
> > > >  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > > +	struct intel_connector *connector = intel_dp->attached_connector;
> > > >
> > > >  	if (!intel_dp_can_bigjoiner(intel_dp))
> > > >  		return false;
> > > >
> > > > -	return clock > i915->max_dotclk_freq || hdisplay > 5120;
> > > > +	return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
> > > > +	       connector->force_bigjoiner_enable;
> > > 
> > > I'm just not comfortable with the magic _show of that macro and would prefer a
> > > more simple and straight forward and widely used version.
> > > 
> > > Other then that everything else looks good to me.
> > > 
> > > Thanks,
> > > Rodrigo.
> > > 
> > > >  }
> > > >
> > > >  static enum drm_mode_status
> > > > --
> > > > 2.42.0
> > > >

Stanislav Lisovskiy Feb. 14, 2024, 9:56 a.m. UTC | #6

On Tue, Feb 13, 2024 at 10:33:56AM -0500, Rodrigo Vivi wrote:
> On Tue, Feb 13, 2024 at 05:21:26PM +0200, Lisovskiy, Stanislav wrote:
> > On Tue, Feb 13, 2024 at 05:11:37PM +0200, Shankar, Uma wrote:
> > > 
> > > 
> > > > -----Original Message-----
> > > > From: Rodrigo Vivi <[e-mail]>
> > > > Sent: Tuesday, February 13, 2024 8:26 PM
> > > > To: Shankar, Uma <[e-mail]>
> > > > Cc: [e-mail]; Lisovskiy, Stanislav
> > > > <[e-mail]>; [e-mail];
> > > > [e-mail]
> > > > Subject: Re: [PATCH] drm/i915: Add bigjoiner force enable option to debugfs
> > > > 
> > > > On Mon, Feb 12, 2024 at 06:20:11PM +0530, Uma Shankar wrote:
> > > > > From: Stanislav Lisovskiy <[e-mail]>
> > > > >
> > > > > For validation purposes, it might be useful to be able to force
> > > > > Bigjoiner mode, even if current dotclock/resolution do not require
> > > > > that.
> > > > > Lets add such to option to debugfs.
> > > > >
> > > > > v2: - Apparently intel_dp_need_bigjoiner can't be used, when
> > > > >       debugfs entry is created so lets just check manually
> > > > >       the DISPLAY_VER.
> > > > >
> > > > > v3: - Switch to intel_connector from drm_connector(Jani Nikula)
> > > > >     - Remove redundant modeset lock(Jani Nikula)
> > > > >     - Use kstrtobool_from_user for boolean value(Jani Nikula)
> > > > >
> > > > > v4: - Apply the changes to proper function(Jani Nikula)
> > > > >
> > > > > v5: - Removed unnecessary check from i915_bigjoiner_enable_show
> > > > >       (Ville Syrjälä)
> > > > >     - Added eDP connector check to intel_connector_debugfs_add
> > > > >       (Ville Syrjälä)
> > > > >     - Removed debug message in order to prevent dmesg flooding
> > > > >       (Ville Syrjälä)
> > > > >
> > > > > v6: - Assume now always that m->private is intel_connector
> > > > >     - Fixed other similar conflicts
> > > > >
> > > > > v7: - Move bigjoiner force option to intel_connector(Ville Syrjälä)
> > > > >     - Use DEFINE_SHOW_STORE_ATTRIBUTE instead of defining fops
> > > > >       manually.(Ville Syrjälä)
> > > > >
> > > > > v8: - Pass intel_connector to debugfs_create_file, instead of drm_connector.
> > > > >       (Jani Nikula)
> > > > >
> > > > > Signed-off-by: Stanislav Lisovskiy <[e-mail]>
> > > > 
> > > > please remind to sign-off when sending someone else's patch.
> > > 
> > > Oh yeah, sorry missed it. Was filling in for Stan while he was OOO.
> > > @Lisovskiy, Stanislav Please address rest of the comments raised by Rodrigo.
> > 
> > Sorry, had that pushed already in the morning, since it was Acked and I was asked
> > to do it asap.
> 
> no worries. if you are confident that the _show function magically works I trust
> your tests more then my eyes and greps.

Well _definitely_ it should not be about trust, confidence or beliefs :)

See:

#define DEFINE_SHOW_STORE_ATTRIBUTE(__name)				\
static int __name ## _open(struct inode *inode, struct file *file)	\
{									\
	return single_open(file, __name ## _show, inode->i_private);	\
}									\
									\
static const struct file_operations __name ## _fops = {			\
	.owner		= THIS_MODULE,					\
	.open		= __name ## _open,				\
	.read		= seq_read,					\
	.write		= __name ## _write,				\
	.llseek		= seq_lseek,					\
	.release	= single_release,				\
}

In the patch:

+DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
+

means it will use i915_bigjoiner_enable_show function.

which is defined just as it expects in the patch:

+static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
+{
+	struct intel_connector *connector = m->private;
+	struct drm_crtc *crtc;
+
+	crtc = connector->base.state->crtc;
+	if (connector->base.status != connector_status_connected || !crtc)
+		return -ENODEV;
+
+	seq_printf(m, "Bigjoiner enable: %d\n", connector->force_bigjoiner_enable);
+
+	return 0;
+}
+


So I don't see any reason here, why it shouldn't work.
If you do, please tell - we need to fix this then.

Stan


> 
> > 
> > Stan
> > 
> > > 
> > > Regards,
> > > Uma Shankar
> > > 
> > > > > ---
> > > > >  .../drm/i915/display/intel_display_debugfs.c  | 47 +++++++++++++++++++
> > > > >  .../drm/i915/display/intel_display_types.h    |  2 +
> > > > >  drivers/gpu/drm/i915/display/intel_dp.c       |  4 +-
> > > > >  3 files changed, 52 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > > b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > > index 6f2d13c8ccf7..a962b48bcf13 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > > @@ -1391,6 +1391,20 @@ out:	drm_modeset_unlock(&i915-
> > > > >drm.mode_config.connection_mutex);
> > > > >  	return ret;
> > > > >  }
> > > > >
> > > > > +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> > > > > +{
> > > > > +	struct intel_connector *connector = m->private;
> > > > > +	struct drm_crtc *crtc;
> > > > > +
> > > > > +	crtc = connector->base.state->crtc;
> > > > > +	if (connector->base.status != connector_status_connected || !crtc)
> > > > > +		return -ENODEV;
> > > > > +
> > > > > +	seq_printf(m, "Bigjoiner enable: %d\n",
> > > > > +connector->force_bigjoiner_enable);
> > > > 
> > > > probably better with a yes_or_no string?
> > > > 
> > > > > +
> > > > > +	return 0;
> > > > > +}
> > > > > +
> > > > >  static ssize_t i915_dsc_output_format_write(struct file *file,
> > > > >  					    const char __user *ubuf,
> > > > >  					    size_t len, loff_t *offp)
> > > > > @@ -1412,6 +1426,30 @@ static ssize_t i915_dsc_output_format_write(struct
> > > > file *file,
> > > > >  	return len;
> > > > >  }
> > > > >
> > > > > +static ssize_t i915_bigjoiner_enable_write(struct file *file,
> > > > > +					   const char __user *ubuf,
> > > > > +					   size_t len, loff_t *offp)
> > > > > +{
> > > > > +	struct seq_file *m = file->private_data;
> > > > > +	struct intel_connector *connector = m->private;
> > > > > +	struct drm_crtc *crtc;
> > > > > +	bool bigjoiner_en = 0;
> > > > > +	int ret;
> > > > > +
> > > > > +	crtc = connector->base.state->crtc;
> > > > > +	if (connector->base.status != connector_status_connected || !crtc)
> > > > > +		return -ENODEV;
> > > > > +
> > > > > +	ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
> > > > > +	if (ret < 0)
> > > > > +		return ret;
> > > > > +
> > > > > +	connector->force_bigjoiner_enable = bigjoiner_en;
> > > > > +	*offp += len;
> > > > > +
> > > > > +	return len;
> > > > > +}
> > > > > +
> > > > >  static int i915_dsc_output_format_open(struct inode *inode,
> > > > >  				       struct file *file)
> > > > >  {
> > > > > @@ -1505,6 +1543,8 @@ static const struct file_operations
> > > > i915_dsc_fractional_bpp_fops = {
> > > > >  	.write = i915_dsc_fractional_bpp_write  };
> > > > >
> > > > > +DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
> > > > 
> > > > I don't believe this macro here is using the defined _show function, but maybe I'm
> > > > not following that very well since this macro is not widely used.
> > > > 
> > > > What about using DEFINE_SIMPLE_ATTRIBUTE instead?
> > > > 
> > > > > +
> > > > >  /*
> > > > >   * Returns the Current CRTC's bpc.
> > > > >   * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> > > > > @@ -1586,6 +1626,13 @@ void intel_connector_debugfs_add(struct
> > > > intel_connector *connector)
> > > > >  				    connector, &i915_dsc_fractional_bpp_fops);
> > > > >  	}
> > > > >
> > > > > +	if (DISPLAY_VER(i915) >= 11 &&
> > > > > +	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > > > > +	     connector_type == DRM_MODE_CONNECTOR_eDP)) {
> > > > 
> > > > I wish we had a simpler check, but I couldn't find. :/
> > > > 
> > > > > +		debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
> > > > > +				    connector, &i915_bigjoiner_enable_fops);
> > > > > +	}
> > > > > +
> > > > >  	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
> > > > >  	    connector_type == DRM_MODE_CONNECTOR_eDP ||
> > > > >  	    connector_type == DRM_MODE_CONNECTOR_DisplayPort || diff --git
> > > > > a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > index 01eb6e4e6049..0d4012097db1 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > @@ -626,6 +626,8 @@ struct intel_connector {
> > > > >
> > > > >  	struct intel_dp *mst_port;
> > > > >
> > > > > +	bool force_bigjoiner_enable;
> > > > > +
> > > > >  	struct {
> > > > >  		struct drm_dp_aux *dsc_decompression_aux;
> > > > >  		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
> > > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > > b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > > index 5045c34a16be..217196196e50 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > > @@ -1205,11 +1205,13 @@ bool intel_dp_need_bigjoiner(struct intel_dp
> > > > *intel_dp,
> > > > >  			     int hdisplay, int clock)
> > > > >  {
> > > > >  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > > > +	struct intel_connector *connector = intel_dp->attached_connector;
> > > > >
> > > > >  	if (!intel_dp_can_bigjoiner(intel_dp))
> > > > >  		return false;
> > > > >
> > > > > -	return clock > i915->max_dotclk_freq || hdisplay > 5120;
> > > > > +	return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
> > > > > +	       connector->force_bigjoiner_enable;
> > > > 
> > > > I'm just not comfortable with the magic _show of that macro and would prefer a
> > > > more simple and straight forward and widely used version.
> > > > 
> > > > Other then that everything else looks good to me.
> > > > 
> > > > Thanks,
> > > > Rodrigo.
> > > > 
> > > > >  }
> > > > >
> > > > >  static enum drm_mode_status
> > > > > --
> > > > > 2.42.0
> > > > >

Rodrigo Vivi Feb. 14, 2024, 1:51 p.m. UTC | #7

On Wed, Feb 14, 2024 at 11:56:10AM +0200, Lisovskiy, Stanislav wrote:
> On Tue, Feb 13, 2024 at 10:33:56AM -0500, Rodrigo Vivi wrote:
> > On Tue, Feb 13, 2024 at 05:21:26PM +0200, Lisovskiy, Stanislav wrote:
> > > On Tue, Feb 13, 2024 at 05:11:37PM +0200, Shankar, Uma wrote:
> > > > 
> > > > 
> > > > > -----Original Message-----
> > > > > From: Rodrigo Vivi <[e-mail]>
> > > > > Sent: Tuesday, February 13, 2024 8:26 PM
> > > > > To: Shankar, Uma <[e-mail]>
> > > > > Cc: [e-mail]; Lisovskiy, Stanislav
> > > > > <[e-mail]>; [e-mail];
> > > > > [e-mail]
> > > > > Subject: Re: [PATCH] drm/i915: Add bigjoiner force enable option to debugfs
> > > > > 
> > > > > On Mon, Feb 12, 2024 at 06:20:11PM +0530, Uma Shankar wrote:
> > > > > > From: Stanislav Lisovskiy <[e-mail]>
> > > > > >
> > > > > > For validation purposes, it might be useful to be able to force
> > > > > > Bigjoiner mode, even if current dotclock/resolution do not require
> > > > > > that.
> > > > > > Lets add such to option to debugfs.
> > > > > >
> > > > > > v2: - Apparently intel_dp_need_bigjoiner can't be used, when
> > > > > >       debugfs entry is created so lets just check manually
> > > > > >       the DISPLAY_VER.
> > > > > >
> > > > > > v3: - Switch to intel_connector from drm_connector(Jani Nikula)
> > > > > >     - Remove redundant modeset lock(Jani Nikula)
> > > > > >     - Use kstrtobool_from_user for boolean value(Jani Nikula)
> > > > > >
> > > > > > v4: - Apply the changes to proper function(Jani Nikula)
> > > > > >
> > > > > > v5: - Removed unnecessary check from i915_bigjoiner_enable_show
> > > > > >       (Ville Syrjälä)
> > > > > >     - Added eDP connector check to intel_connector_debugfs_add
> > > > > >       (Ville Syrjälä)
> > > > > >     - Removed debug message in order to prevent dmesg flooding
> > > > > >       (Ville Syrjälä)
> > > > > >
> > > > > > v6: - Assume now always that m->private is intel_connector
> > > > > >     - Fixed other similar conflicts
> > > > > >
> > > > > > v7: - Move bigjoiner force option to intel_connector(Ville Syrjälä)
> > > > > >     - Use DEFINE_SHOW_STORE_ATTRIBUTE instead of defining fops
> > > > > >       manually.(Ville Syrjälä)
> > > > > >
> > > > > > v8: - Pass intel_connector to debugfs_create_file, instead of drm_connector.
> > > > > >       (Jani Nikula)
> > > > > >
> > > > > > Signed-off-by: Stanislav Lisovskiy <[e-mail]>
> > > > > 
> > > > > please remind to sign-off when sending someone else's patch.
> > > > 
> > > > Oh yeah, sorry missed it. Was filling in for Stan while he was OOO.
> > > > @Lisovskiy, Stanislav Please address rest of the comments raised by Rodrigo.
> > > 
> > > Sorry, had that pushed already in the morning, since it was Acked and I was asked
> > > to do it asap.
> > 
> > no worries. if you are confident that the _show function magically works I trust
> > your tests more then my eyes and greps.
> 
> Well _definitely_ it should not be about trust, confidence or beliefs :)
> 
> See:
> 
> #define DEFINE_SHOW_STORE_ATTRIBUTE(__name)				\
> static int __name ## _open(struct inode *inode, struct file *file)	\
> {									\
> 	return single_open(file, __name ## _show, inode->i_private);	\

                                           ^
this was the part that I was missing! Thanks for pointing that out.
I was looking the definition below, but was missing the jump from the
_open to _show... I hate macro indirections.

Thanks pointing that out.

> }									\
> 									\
> static const struct file_operations __name ## _fops = {			\
> 	.owner		= THIS_MODULE,					\
> 	.open		= __name ## _open,				\
> 	.read		= seq_read,					\
> 	.write		= __name ## _write,				\
> 	.llseek		= seq_lseek,					\
> 	.release	= single_release,				\
> }
> 
> In the patch:
> 
> +DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
> +
> 
> means it will use i915_bigjoiner_enable_show function.
> 
> which is defined just as it expects in the patch:
> 
> +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> +{
> +	struct intel_connector *connector = m->private;
> +	struct drm_crtc *crtc;
> +
> +	crtc = connector->base.state->crtc;
> +	if (connector->base.status != connector_status_connected || !crtc)
> +		return -ENODEV;
> +
> +	seq_printf(m, "Bigjoiner enable: %d\n", connector->force_bigjoiner_enable);
> +
> +	return 0;
> +}
> +
> 
> 
> So I don't see any reason here, why it shouldn't work.
> If you do, please tell - we need to fix this then.
> 
> Stan
> 
> 
> > 
> > > 
> > > Stan
> > > 
> > > > 
> > > > Regards,
> > > > Uma Shankar
> > > > 
> > > > > > ---
> > > > > >  .../drm/i915/display/intel_display_debugfs.c  | 47 +++++++++++++++++++
> > > > > >  .../drm/i915/display/intel_display_types.h    |  2 +
> > > > > >  drivers/gpu/drm/i915/display/intel_dp.c       |  4 +-
> > > > > >  3 files changed, 52 insertions(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > > > b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > > > index 6f2d13c8ccf7..a962b48bcf13 100644
> > > > > > --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> > > > > > @@ -1391,6 +1391,20 @@ out:	drm_modeset_unlock(&i915-
> > > > > >drm.mode_config.connection_mutex);
> > > > > >  	return ret;
> > > > > >  }
> > > > > >
> > > > > > +static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
> > > > > > +{
> > > > > > +	struct intel_connector *connector = m->private;
> > > > > > +	struct drm_crtc *crtc;
> > > > > > +
> > > > > > +	crtc = connector->base.state->crtc;
> > > > > > +	if (connector->base.status != connector_status_connected || !crtc)
> > > > > > +		return -ENODEV;
> > > > > > +
> > > > > > +	seq_printf(m, "Bigjoiner enable: %d\n",
> > > > > > +connector->force_bigjoiner_enable);
> > > > > 
> > > > > probably better with a yes_or_no string?
> > > > > 
> > > > > > +
> > > > > > +	return 0;
> > > > > > +}
> > > > > > +
> > > > > >  static ssize_t i915_dsc_output_format_write(struct file *file,
> > > > > >  					    const char __user *ubuf,
> > > > > >  					    size_t len, loff_t *offp)
> > > > > > @@ -1412,6 +1426,30 @@ static ssize_t i915_dsc_output_format_write(struct
> > > > > file *file,
> > > > > >  	return len;
> > > > > >  }
> > > > > >
> > > > > > +static ssize_t i915_bigjoiner_enable_write(struct file *file,
> > > > > > +					   const char __user *ubuf,
> > > > > > +					   size_t len, loff_t *offp)
> > > > > > +{
> > > > > > +	struct seq_file *m = file->private_data;
> > > > > > +	struct intel_connector *connector = m->private;
> > > > > > +	struct drm_crtc *crtc;
> > > > > > +	bool bigjoiner_en = 0;
> > > > > > +	int ret;
> > > > > > +
> > > > > > +	crtc = connector->base.state->crtc;
> > > > > > +	if (connector->base.status != connector_status_connected || !crtc)
> > > > > > +		return -ENODEV;
> > > > > > +
> > > > > > +	ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
> > > > > > +	if (ret < 0)
> > > > > > +		return ret;
> > > > > > +
> > > > > > +	connector->force_bigjoiner_enable = bigjoiner_en;
> > > > > > +	*offp += len;
> > > > > > +
> > > > > > +	return len;
> > > > > > +}
> > > > > > +
> > > > > >  static int i915_dsc_output_format_open(struct inode *inode,
> > > > > >  				       struct file *file)
> > > > > >  {
> > > > > > @@ -1505,6 +1543,8 @@ static const struct file_operations
> > > > > i915_dsc_fractional_bpp_fops = {
> > > > > >  	.write = i915_dsc_fractional_bpp_write  };
> > > > > >
> > > > > > +DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
> > > > > 
> > > > > I don't believe this macro here is using the defined _show function, but maybe I'm
> > > > > not following that very well since this macro is not widely used.
> > > > > 
> > > > > What about using DEFINE_SIMPLE_ATTRIBUTE instead?
> > > > > 
> > > > > > +
> > > > > >  /*
> > > > > >   * Returns the Current CRTC's bpc.
> > > > > >   * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
> > > > > > @@ -1586,6 +1626,13 @@ void intel_connector_debugfs_add(struct
> > > > > intel_connector *connector)
> > > > > >  				    connector, &i915_dsc_fractional_bpp_fops);
> > > > > >  	}
> > > > > >
> > > > > > +	if (DISPLAY_VER(i915) >= 11 &&
> > > > > > +	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
> > > > > > +	     connector_type == DRM_MODE_CONNECTOR_eDP)) {
> > > > > 
> > > > > I wish we had a simpler check, but I couldn't find. :/
> > > > > 
> > > > > > +		debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
> > > > > > +				    connector, &i915_bigjoiner_enable_fops);
> > > > > > +	}
> > > > > > +
> > > > > >  	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
> > > > > >  	    connector_type == DRM_MODE_CONNECTOR_eDP ||
> > > > > >  	    connector_type == DRM_MODE_CONNECTOR_DisplayPort || diff --git
> > > > > > a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > > index 01eb6e4e6049..0d4012097db1 100644
> > > > > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > > @@ -626,6 +626,8 @@ struct intel_connector {
> > > > > >
> > > > > >  	struct intel_dp *mst_port;
> > > > > >
> > > > > > +	bool force_bigjoiner_enable;
> > > > > > +
> > > > > >  	struct {
> > > > > >  		struct drm_dp_aux *dsc_decompression_aux;
> > > > > >  		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
> > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > > > b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > > > index 5045c34a16be..217196196e50 100644
> > > > > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > > > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > > > > @@ -1205,11 +1205,13 @@ bool intel_dp_need_bigjoiner(struct intel_dp
> > > > > *intel_dp,
> > > > > >  			     int hdisplay, int clock)
> > > > > >  {
> > > > > >  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> > > > > > +	struct intel_connector *connector = intel_dp->attached_connector;
> > > > > >
> > > > > >  	if (!intel_dp_can_bigjoiner(intel_dp))
> > > > > >  		return false;
> > > > > >
> > > > > > -	return clock > i915->max_dotclk_freq || hdisplay > 5120;
> > > > > > +	return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
> > > > > > +	       connector->force_bigjoiner_enable;
> > > > > 
> > > > > I'm just not comfortable with the magic _show of that macro and would prefer a
> > > > > more simple and straight forward and widely used version.
> > > > > 
> > > > > Other then that everything else looks good to me.
> > > > > 
> > > > > Thanks,
> > > > > Rodrigo.
> > > > > 
> > > > > >  }
> > > > > >
> > > > > >  static enum drm_mode_status
> > > > > > --
> > > > > > 2.42.0
> > > > > >

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
index 6f2d13c8ccf7..a962b48bcf13 100644
--- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
+++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
@@ -1391,6 +1391,20 @@  out:	drm_modeset_unlock(&i915->drm.mode_config.connection_mutex);
 	return ret;
 }
 
+static int i915_bigjoiner_enable_show(struct seq_file *m, void *data)
+{
+	struct intel_connector *connector = m->private;
+	struct drm_crtc *crtc;
+
+	crtc = connector->base.state->crtc;
+	if (connector->base.status != connector_status_connected || !crtc)
+		return -ENODEV;
+
+	seq_printf(m, "Bigjoiner enable: %d\n", connector->force_bigjoiner_enable);
+
+	return 0;
+}
+
 static ssize_t i915_dsc_output_format_write(struct file *file,
 					    const char __user *ubuf,
 					    size_t len, loff_t *offp)
@@ -1412,6 +1426,30 @@  static ssize_t i915_dsc_output_format_write(struct file *file,
 	return len;
 }
 
+static ssize_t i915_bigjoiner_enable_write(struct file *file,
+					   const char __user *ubuf,
+					   size_t len, loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	struct intel_connector *connector = m->private;
+	struct drm_crtc *crtc;
+	bool bigjoiner_en = 0;
+	int ret;
+
+	crtc = connector->base.state->crtc;
+	if (connector->base.status != connector_status_connected || !crtc)
+		return -ENODEV;
+
+	ret = kstrtobool_from_user(ubuf, len, &bigjoiner_en);
+	if (ret < 0)
+		return ret;
+
+	connector->force_bigjoiner_enable = bigjoiner_en;
+	*offp += len;
+
+	return len;
+}
+
 static int i915_dsc_output_format_open(struct inode *inode,
 				       struct file *file)
 {
@@ -1505,6 +1543,8 @@  static const struct file_operations i915_dsc_fractional_bpp_fops = {
 	.write = i915_dsc_fractional_bpp_write
 };
 
+DEFINE_SHOW_STORE_ATTRIBUTE(i915_bigjoiner_enable);
+
 /*
  * Returns the Current CRTC's bpc.
  * Example usage: cat /sys/kernel/debug/dri/0/crtc-0/i915_current_bpc
@@ -1586,6 +1626,13 @@  void intel_connector_debugfs_add(struct intel_connector *connector)
 				    connector, &i915_dsc_fractional_bpp_fops);
 	}
 
+	if (DISPLAY_VER(i915) >= 11 &&
+	    (connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
+	     connector_type == DRM_MODE_CONNECTOR_eDP)) {
+		debugfs_create_file("i915_bigjoiner_force_enable", 0644, root,
+				    connector, &i915_bigjoiner_enable_fops);
+	}
+
 	if (connector_type == DRM_MODE_CONNECTOR_DSI ||
 	    connector_type == DRM_MODE_CONNECTOR_eDP ||
 	    connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 01eb6e4e6049..0d4012097db1 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -626,6 +626,8 @@  struct intel_connector {
 
 	struct intel_dp *mst_port;
 
+	bool force_bigjoiner_enable;
+
 	struct {
 		struct drm_dp_aux *dsc_decompression_aux;
 		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 5045c34a16be..217196196e50 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1205,11 +1205,13 @@  bool intel_dp_need_bigjoiner(struct intel_dp *intel_dp,
 			     int hdisplay, int clock)
 {
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+	struct intel_connector *connector = intel_dp->attached_connector;
 
 	if (!intel_dp_can_bigjoiner(intel_dp))
 		return false;
 
-	return clock > i915->max_dotclk_freq || hdisplay > 5120;
+	return clock > i915->max_dotclk_freq || hdisplay > 5120 ||
+	       connector->force_bigjoiner_enable;
 }
 
 static enum drm_mode_status