diff mbox series

[v2] drm/edid: Fix csync detailed mode parsing

Message ID 20230228213610.26283-1-ville.syrjala@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series [v2] drm/edid: Fix csync detailed mode parsing | expand

Commit Message

Ville Syrjälä Feb. 28, 2023, 9:36 p.m. UTC
From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Remove the bogus csync check and replace it with something that:
- triggers for all forms of csync, not just the basic analog variant
- actually populates the mode csync flags so that drivers can
  decide what to do with the mode

Originally the code tried to outright reject csync, but that
apparently broke some bogus LCD monitor that claimed to have
a detailed mode that uses analog csync, despite also claiming
the monitor only support separate sync:
https://bugzilla.redhat.com/show_bug.cgi?id=540024
Potentially that monitor should just be quirked or something.

Anyways, what we are dealing with now is some kind of funny i915
JSL machine with eDP where the panel claims to support a sensible
60Hz separate sync mode, and a 50Hz mode with bipolar analog
csync. The 50Hz mode does not work so we want to not use it.
Easiest way is to just correctly flag it as csync and the driver
will reject it.

TODO: or should we just reject any form of csync (or at least
the analog variants) for digital display interfaces?

v2: Grab digital csync polarity from hsync polarity bit (Jani)

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8146
Reviewed-by: Jani Nikula <jani.nikula@intel.com> #v1
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/drm_edid.c | 29 +++++++++++++++++++++--------
 include/drm/drm_edid.h     | 12 +++++++++---
 2 files changed, 30 insertions(+), 11 deletions(-)

Comments

Jani Nikula March 1, 2023, 8:49 a.m. UTC | #1
On Tue, 28 Feb 2023, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Remove the bogus csync check and replace it with something that:
> - triggers for all forms of csync, not just the basic analog variant
> - actually populates the mode csync flags so that drivers can
>   decide what to do with the mode
>
> Originally the code tried to outright reject csync, but that
> apparently broke some bogus LCD monitor that claimed to have
> a detailed mode that uses analog csync, despite also claiming
> the monitor only support separate sync:
> https://bugzilla.redhat.com/show_bug.cgi?id=540024
> Potentially that monitor should just be quirked or something.
>
> Anyways, what we are dealing with now is some kind of funny i915
> JSL machine with eDP where the panel claims to support a sensible
> 60Hz separate sync mode, and a 50Hz mode with bipolar analog
> csync. The 50Hz mode does not work so we want to not use it.
> Easiest way is to just correctly flag it as csync and the driver
> will reject it.
>
> TODO: or should we just reject any form of csync (or at least
> the analog variants) for digital display interfaces?
>
> v2: Grab digital csync polarity from hsync polarity bit (Jani)
>
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8146
> Reviewed-by: Jani Nikula <jani.nikula@intel.com> #v1

Yup. Fingers crossed.

> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c | 29 +++++++++++++++++++++--------
>  include/drm/drm_edid.h     | 12 +++++++++---
>  2 files changed, 30 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index ebab862b8b1a..c18ec866678d 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -3424,10 +3424,6 @@ static struct drm_display_mode *drm_mode_detailed(struct drm_connector *connecto
>  			    connector->base.id, connector->name);
>  		return NULL;
>  	}
> -	if (!(pt->misc & DRM_EDID_PT_SEPARATE_SYNC)) {
> -		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Composite sync not supported\n",
> -			    connector->base.id, connector->name);
> -	}
>  
>  	/* it is incorrect if hsync/vsync width is zero */
>  	if (!hsync_pulse_width || !vsync_pulse_width) {
> @@ -3474,10 +3470,27 @@ static struct drm_display_mode *drm_mode_detailed(struct drm_connector *connecto
>  	if (info->quirks & EDID_QUIRK_DETAILED_SYNC_PP) {
>  		mode->flags |= DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC;
>  	} else {
> -		mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
> -			DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
> -		mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
> -			DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
> +		switch (pt->misc & DRM_EDID_PT_SYNC_MASK) {
> +		case DRM_EDID_PT_ANALOG_CSYNC:
> +		case DRM_EDID_PT_BIPOLAR_ANALOG_CSYNC:
> +			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Analog composite sync!\n",
> +				    connector->base.id, connector->name);
> +			mode->flags |= DRM_MODE_FLAG_CSYNC | DRM_MODE_FLAG_NCSYNC;
> +			break;
> +		case DRM_EDID_PT_DIGITAL_CSYNC:
> +			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Digital composite sync!\n",
> +				    connector->base.id, connector->name);
> +			mode->flags |= DRM_MODE_FLAG_CSYNC;
> +			mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
> +				DRM_MODE_FLAG_PCSYNC : DRM_MODE_FLAG_NCSYNC;
> +			break;
> +		case DRM_EDID_PT_DIGITAL_SEPARATE_SYNC:
> +			mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
> +				DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
> +			mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
> +				DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
> +			break;
> +		}
>  	}
>  
>  set_size:
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index 70ae6c290bdc..571885d32907 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -61,9 +61,15 @@ struct std_timing {
>  	u8 vfreq_aspect;
>  } __attribute__((packed));
>  
> -#define DRM_EDID_PT_HSYNC_POSITIVE (1 << 1)
> -#define DRM_EDID_PT_VSYNC_POSITIVE (1 << 2)
> -#define DRM_EDID_PT_SEPARATE_SYNC  (3 << 3)
> +#define DRM_EDID_PT_SYNC_MASK              (3 << 3)
> +# define DRM_EDID_PT_ANALOG_CSYNC          (0 << 3)
> +# define DRM_EDID_PT_BIPOLAR_ANALOG_CSYNC  (1 << 3)
> +# define DRM_EDID_PT_DIGITAL_CSYNC         (2 << 3)
> +#  define DRM_EDID_PT_CSYNC_ON_RGB         (1 << 1) /* analog csync only */
> +#  define DRM_EDID_PT_CSYNC_SERRATE        (1 << 2)
> +# define DRM_EDID_PT_DIGITAL_SEPARATE_SYNC (3 << 3)
> +#  define DRM_EDID_PT_HSYNC_POSITIVE       (1 << 1) /* also digital csync */
> +#  define DRM_EDID_PT_VSYNC_POSITIVE       (1 << 2)
>  #define DRM_EDID_PT_STEREO         (1 << 5)
>  #define DRM_EDID_PT_INTERLACED     (1 << 7)
Ville Syrjälä March 1, 2023, 3:05 p.m. UTC | #2
On Wed, Mar 01, 2023 at 10:49:26AM +0200, Jani Nikula wrote:
> On Tue, 28 Feb 2023, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Remove the bogus csync check and replace it with something that:
> > - triggers for all forms of csync, not just the basic analog variant
> > - actually populates the mode csync flags so that drivers can
> >   decide what to do with the mode
> >
> > Originally the code tried to outright reject csync, but that
> > apparently broke some bogus LCD monitor that claimed to have
> > a detailed mode that uses analog csync, despite also claiming
> > the monitor only support separate sync:
> > https://bugzilla.redhat.com/show_bug.cgi?id=540024
> > Potentially that monitor should just be quirked or something.
> >
> > Anyways, what we are dealing with now is some kind of funny i915
> > JSL machine with eDP where the panel claims to support a sensible
> > 60Hz separate sync mode, and a 50Hz mode with bipolar analog
> > csync. The 50Hz mode does not work so we want to not use it.
> > Easiest way is to just correctly flag it as csync and the driver
> > will reject it.
> >
> > TODO: or should we just reject any form of csync (or at least
> > the analog variants) for digital display interfaces?
> >
> > v2: Grab digital csync polarity from hsync polarity bit (Jani)
> >
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8146
> > Reviewed-by: Jani Nikula <jani.nikula@intel.com> #v1
> 
> Yup. Fingers crossed.

Thought it best to give this plenty of time to soak, so pushed
to drm-misc-next. Thanks for the review.
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index ebab862b8b1a..c18ec866678d 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3424,10 +3424,6 @@  static struct drm_display_mode *drm_mode_detailed(struct drm_connector *connecto
 			    connector->base.id, connector->name);
 		return NULL;
 	}
-	if (!(pt->misc & DRM_EDID_PT_SEPARATE_SYNC)) {
-		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Composite sync not supported\n",
-			    connector->base.id, connector->name);
-	}
 
 	/* it is incorrect if hsync/vsync width is zero */
 	if (!hsync_pulse_width || !vsync_pulse_width) {
@@ -3474,10 +3470,27 @@  static struct drm_display_mode *drm_mode_detailed(struct drm_connector *connecto
 	if (info->quirks & EDID_QUIRK_DETAILED_SYNC_PP) {
 		mode->flags |= DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC;
 	} else {
-		mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
-			DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
-		mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
-			DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
+		switch (pt->misc & DRM_EDID_PT_SYNC_MASK) {
+		case DRM_EDID_PT_ANALOG_CSYNC:
+		case DRM_EDID_PT_BIPOLAR_ANALOG_CSYNC:
+			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Analog composite sync!\n",
+				    connector->base.id, connector->name);
+			mode->flags |= DRM_MODE_FLAG_CSYNC | DRM_MODE_FLAG_NCSYNC;
+			break;
+		case DRM_EDID_PT_DIGITAL_CSYNC:
+			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Digital composite sync!\n",
+				    connector->base.id, connector->name);
+			mode->flags |= DRM_MODE_FLAG_CSYNC;
+			mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
+				DRM_MODE_FLAG_PCSYNC : DRM_MODE_FLAG_NCSYNC;
+			break;
+		case DRM_EDID_PT_DIGITAL_SEPARATE_SYNC:
+			mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
+				DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
+			mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
+				DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
+			break;
+		}
 	}
 
 set_size:
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 70ae6c290bdc..571885d32907 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -61,9 +61,15 @@  struct std_timing {
 	u8 vfreq_aspect;
 } __attribute__((packed));
 
-#define DRM_EDID_PT_HSYNC_POSITIVE (1 << 1)
-#define DRM_EDID_PT_VSYNC_POSITIVE (1 << 2)
-#define DRM_EDID_PT_SEPARATE_SYNC  (3 << 3)
+#define DRM_EDID_PT_SYNC_MASK              (3 << 3)
+# define DRM_EDID_PT_ANALOG_CSYNC          (0 << 3)
+# define DRM_EDID_PT_BIPOLAR_ANALOG_CSYNC  (1 << 3)
+# define DRM_EDID_PT_DIGITAL_CSYNC         (2 << 3)
+#  define DRM_EDID_PT_CSYNC_ON_RGB         (1 << 1) /* analog csync only */
+#  define DRM_EDID_PT_CSYNC_SERRATE        (1 << 2)
+# define DRM_EDID_PT_DIGITAL_SEPARATE_SYNC (3 << 3)
+#  define DRM_EDID_PT_HSYNC_POSITIVE       (1 << 1) /* also digital csync */
+#  define DRM_EDID_PT_VSYNC_POSITIVE       (1 << 2)
 #define DRM_EDID_PT_STEREO         (1 << 5)
 #define DRM_EDID_PT_INTERLACED     (1 << 7)