Re: [PATCH v3] drm/i915/edp: Add a T12 panel delay quirk to fix DP AUX CH timeouts

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Jun 29, 2017 at 02:10:38PM -0700, Manasi Navare wrote:
> This patch fixes the DP AUX CH timeouts observed during CI IGT
> tests thus fixing the CI failures. This is done by adding a
> quirk for a particular PCI device that requires the panel power
> cycle delay (T12) to be set to 800ms which is 300msecs more than
> the minimum value specified in the eDP spec. So a quirk is
> implemented for that specific PCI device.
> 
> v3:
> * Change some comments, specify the delay as 800 * 10 (Ville)
> v2:
> * Change the function and variable names to from PPS_T12_
> to _T12 since it is a T12 delay (Clint)
> 
> Fixes: FDO #101144 #101515 #101154 #101167

That's not how we do it.

Also please look into git send-email --in-reply-to option. Review is
easier if the patches aren't spread all over the mailbox.

> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> Cc: Clinton Taylor <clinton.a.taylor@intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> Reviewed-by: Clinton Taylor <clinton.a.taylor@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h      |  1 +
>  drivers/gpu/drm/i915/intel_display.c | 14 ++++++++++++++
>  drivers/gpu/drm/i915/intel_dp.c      | 11 +++++++++++
>  3 files changed, 26 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 427d10c..4327c8a 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1168,6 +1168,7 @@ enum intel_sbi_destination {
>  #define QUIRK_INVERT_BRIGHTNESS (1<<2)
>  #define QUIRK_BACKLIGHT_PRESENT (1<<3)
>  #define QUIRK_PIN_SWIZZLED_PAGES (1<<5)
> +#define QUIRK_INCREASE_T12_DELAY (1<<6)
>  
>  struct intel_fbdev;
>  struct intel_fbc_work;
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 4e03ca6..87dfde9 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -14765,6 +14765,17 @@ static void quirk_backlight_present(struct drm_device *dev)
>  	DRM_INFO("applying backlight present quirk\n");
>  }
>  
> +/* Toshiba Satellite P50-C-18C requires T12 delay to be min 800ms
> + * which is 300 ms greater than eDP spec T12 min.
> + */
> +static void quirk_increase_t12_delay(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +
> +	dev_priv->quirks |= QUIRK_INCREASE_T12_DELAY;
> +	DRM_INFO("Applying T12 delay quirk\n");
> +}
> +
>  struct intel_quirk {
>  	int device;
>  	int subsystem_vendor;
> @@ -14848,6 +14859,9 @@ static struct intel_quirk intel_quirks[] = {
>  
>  	/* Dell Chromebook 11 (2015 version) */
>  	{ 0x0a16, 0x1028, 0x0a35, quirk_backlight_present },
> +
> +	/* Toshiba Satellite P50-C-18C */
> +	{ 0x191B, 0x1179, 0xF840, quirk_increase_t12_delay },
>  };
>  
>  static void intel_init_quirks(struct drm_device *dev)
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 67bc8a7a..4d7e510 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -5230,6 +5230,17 @@ intel_dp_init_panel_power_sequencer(struct drm_device *dev,
>  	intel_pps_dump_state("cur", &cur);
>  
>  	vbt = dev_priv->vbt.edp.pps;
> +	/* On Toshiba Satellite P50-C-18C system the VBT T12 delay
> +	 * of 500ms appears to be too short. Ocassionally the panel
> +	 * just fails to power back on. Increasing the delay to 800ms
> +	 * seems sufficient to avpid this problem.a
                                 ^
typo

Otherwise looks OK to me.

> +	 */
> +	if (dev_priv->quirks & QUIRK_INCREASE_T12_DELAY) {
> +
> +		vbt.t11_t12 = max_t(u16, vbt.t11_t12, 800 * 10);
> +		DRM_DEBUG_KMS("Increasing T12 panel delay as per the quirk to %d\n",
> +			      vbt.t11_t12);
> +	}
>  	/* T11_T12 delay is special and actually in units of 100ms, but zero
>  	 * based in the hw (so we need to add 100 ms). But the sw vbt
>  	 * table multiplies it with 1000 to make it in units of 100usec,
> -- 
> 2.1.4

-- 
Ville Syrjälä
Intel OTC
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