diff mbox

[RESEND,v4,2/6] drm/i915: Correctly enable blacklight adjustment via DPCD

Message ID 20170418234824.157355-3-puthik@chromium.org (mailing list archive)
State New, archived
Headers show

Commit Message

Puthikorn Voravootivat April 18, 2017, 11:48 p.m. UTC 
intel_dp_aux_enable_backlight() assumed that the register
BACKLIGHT_BRIGHTNESS_CONTROL_MODE can only has value 01
(DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET) when initialize.

This patch fixed that by handling all cases of that register.

Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>
---
 drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 29 +++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

Comments

Dhinakaran Pandiyan May 3, 2017, 12:56 a.m. UTC | #1 
On Tue, 2017-04-18 at 16:48 -0700, Puthikorn Voravootivat wrote:
> intel_dp_aux_enable_backlight() assumed that the register

> BACKLIGHT_BRIGHTNESS_CONTROL_MODE can only has value 01

> (DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET) when initialize.

> 

> This patch fixed that by handling all cases of that register.

> 

> Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>

> ---

>  drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 29 +++++++++++++++++++++------

>  1 file changed, 23 insertions(+), 6 deletions(-)

> 

> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c

> index 42f73d9a3ccf..f06c8381c74e 100644

> --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c

> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c

> @@ -101,15 +101,32 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector)

>  {

>  	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);

>  	uint8_t dpcd_buf = 0;

> +	uint8_t edp_backlight_mode = 0;

>  

>  	set_aux_backlight_enable(intel_dp, true);

>  

> -	if ((drm_dp_dpcd_readb(&intel_dp->aux,

> -			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) == 1) &&

> -	    ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) ==

> -	     DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET))

> -		drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,

> -				   (dpcd_buf | DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD));

> +	if (!drm_dp_dpcd_readb(&intel_dp->aux,

> +			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf)) {

> +		return;

> +	}

> +

> +	edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;

> +

> +	switch (edp_backlight_mode) {

> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:

> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:

> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:

> +		dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;

> +		dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;

> +		drm_dp_dpcd_writeb(&intel_dp->aux,

> +			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf);



You check the return value for _readb() above, but don't check for the
_writeb() here.



> +		break;

> +

> +	/* Do nothing when it is already DPCD mode */

> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:

> +	default:

> +		break;

> +	}

>  }

>  

>  static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
Dhinakaran Pandiyan May 3, 2017, 1:17 a.m. UTC | #2 
Adjusting "blacklight" probably won't make a lot of difference even if
done correctly:) Typo in the patch subject.

-DK


On Tue, 2017-04-18 at 16:48 -0700, Puthikorn Voravootivat wrote:
> intel_dp_aux_enable_backlight() assumed that the register

> BACKLIGHT_BRIGHTNESS_CONTROL_MODE can only has value 01

> (DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET) when initialize.

> 

> This patch fixed that by handling all cases of that register.

> 

> Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>

> ---

>  drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 29 +++++++++++++++++++++------

>  1 file changed, 23 insertions(+), 6 deletions(-)

> 

> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c

> index 42f73d9a3ccf..f06c8381c74e 100644

> --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c

> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c

> @@ -101,15 +101,32 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector)

>  {

>  	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);

>  	uint8_t dpcd_buf = 0;

> +	uint8_t edp_backlight_mode = 0;

>  

>  	set_aux_backlight_enable(intel_dp, true);

>  

> -	if ((drm_dp_dpcd_readb(&intel_dp->aux,

> -			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) == 1) &&

> -	    ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) ==

> -	     DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET))

> -		drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,

> -				   (dpcd_buf | DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD));

> +	if (!drm_dp_dpcd_readb(&intel_dp->aux,

> +			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf)) {

> +		return;

> +	}

> +

> +	edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;

> +

> +	switch (edp_backlight_mode) {

> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:

> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:

> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:

> +		dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;

> +		dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;

> +		drm_dp_dpcd_writeb(&intel_dp->aux,

> +			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf);

> +		break;

> +

> +	/* Do nothing when it is already DPCD mode */

> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:

> +	default:

> +		break;

> +	}

>  }

>  

>  static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
Navare, Manasi May 3, 2017, 2 a.m. UTC | #3 
On Tue, Apr 18, 2017 at 04:48:20PM -0700, Puthikorn Voravootivat wrote:
> intel_dp_aux_enable_backlight() assumed that the register
> BACKLIGHT_BRIGHTNESS_CONTROL_MODE can only has value 01
> (DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET) when initialize.
> 
> This patch fixed that by handling all cases of that register.
> 
> Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>
> ---
>  drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 29 +++++++++++++++++++++------
>  1 file changed, 23 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> index 42f73d9a3ccf..f06c8381c74e 100644
> --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> @@ -101,15 +101,32 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
>  {
>  	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
>  	uint8_t dpcd_buf = 0;
> +	uint8_t edp_backlight_mode = 0;
>  
>  	set_aux_backlight_enable(intel_dp, true);
>  
> -	if ((drm_dp_dpcd_readb(&intel_dp->aux,
> -			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) == 1) &&
> -	    ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) ==
> -	     DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET))
> -		drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
> -				   (dpcd_buf | DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD));
> +	if (!drm_dp_dpcd_readb(&intel_dp->aux,
> +			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf)) {
> +		return;
> +	}
> +
> +	edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> +
> +	switch (edp_backlight_mode) {
> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
> +		dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> +		dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
> +		drm_dp_dpcd_writeb(&intel_dp->aux,
> +			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf);
> +		break;
> +
> +	/* Do nothing when it is already DPCD mode */
> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:
> +	default:
> +		break;

Do you really need a break; here?

Manasi
> +	}
>  }
>  
>  static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
> -- 
> 2.12.2.816.g2cccc81164-goog
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Jani Nikula May 3, 2017, 9:19 a.m. UTC | #4 
On Tue, 18 Apr 2017, Puthikorn Voravootivat <puthik@chromium.org> wrote:
> intel_dp_aux_enable_backlight() assumed that the register
> BACKLIGHT_BRIGHTNESS_CONTROL_MODE can only has value 01
> (DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET) when initialize.
>
> This patch fixed that by handling all cases of that register.

Fixes like this should precede the functional changes, i.e. this should
be earlier in the series.

>
> Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org>
> ---
>  drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 29 +++++++++++++++++++++------
>  1 file changed, 23 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> index 42f73d9a3ccf..f06c8381c74e 100644
> --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> @@ -101,15 +101,32 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
>  {
>  	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
>  	uint8_t dpcd_buf = 0;
> +	uint8_t edp_backlight_mode = 0;
>  
>  	set_aux_backlight_enable(intel_dp, true);
>  
> -	if ((drm_dp_dpcd_readb(&intel_dp->aux,
> -			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) == 1) &&
> -	    ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) ==
> -	     DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET))
> -		drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
> -				   (dpcd_buf | DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD));

Ugh, that's really totally busted, since this actually enables the
product mode because it doesn't mask out the preset first. Thanks for
fixing this.

> +	if (!drm_dp_dpcd_readb(&intel_dp->aux,
> +			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf)) {

I don't think there are any valid scenarious where this call would
return 0. if (... != 1) is the right check.

> +		return;
> +	}
> +
> +	edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> +
> +	switch (edp_backlight_mode) {
> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
> +		dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
> +		dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
> +		drm_dp_dpcd_writeb(&intel_dp->aux,
> +			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf);

I wonder if the right order would be to set the mode first, and call
set_aux_backlight_enable() after that. I couldn't find anything about
that in the spec, but gut feeling says that would be better. Needs to be
a separate change though.

BR,
Jani.

> +		break;
> +
> +	/* Do nothing when it is already DPCD mode */
> +	case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:
> +	default:
> +		break;
> +	}
>  }
>  
>  static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
index 42f73d9a3ccf..f06c8381c74e 100644
--- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
@@ -101,15 +101,32 @@  static void intel_dp_aux_enable_backlight(struct intel_connector *connector)
 {
 	struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base);
 	uint8_t dpcd_buf = 0;
+	uint8_t edp_backlight_mode = 0;
 
 	set_aux_backlight_enable(intel_dp, true);
 
-	if ((drm_dp_dpcd_readb(&intel_dp->aux,
-			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) == 1) &&
-	    ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) ==
-	     DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET))
-		drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
-				   (dpcd_buf | DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD));
+	if (!drm_dp_dpcd_readb(&intel_dp->aux,
+			       DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf)) {
+		return;
+	}
+
+	edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
+
+	switch (edp_backlight_mode) {
+	case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM:
+	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET:
+	case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT:
+		dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK;
+		dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD;
+		drm_dp_dpcd_writeb(&intel_dp->aux,
+			DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf);
+		break;
+
+	/* Do nothing when it is already DPCD mode */
+	case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD:
+	default:
+		break;
+	}
 }
 
 static void intel_dp_aux_disable_backlight(struct intel_connector *connector)