[Intel-gfx] [PATCH v2] drm/i915/edp: Add a T12 panel delay quirk to fix DP AUX CH timeouts

[Clint Taylor]

Looks Good.
Reviewed-by: Clinton Taylor <clinton.a.taylor at intel.com>

-Clint


On 06/28/2017 05:14 PM, 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 300msecs more than the minimum value
> specified in the eDP spec. So a quirk is implemented for that
> specific PCI device.
>
> 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
> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> Cc: Cinton Taylor <clinton.a.taylor at intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_drv.h      |  1 +
>   drivers/gpu/drm/i915/intel_display.c | 12 ++++++++++++
>   drivers/gpu/drm/i915/intel_dp.c      | 12 ++++++++++++
>   3 files changed, 25 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..37beb62 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -14765,6 +14765,15 @@ static void quirk_backlight_present(struct drm_device *dev)
>   	DRM_INFO("applying backlight present quirk\n");
>   }
>   
> +/* Some systems require 300ms extra PPS T12 delay to be added to VBT value */
> +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 +14857,9 @@ 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..db6953e 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -49,6 +49,9 @@
>   #define INTEL_DP_RESOLUTION_STANDARD	(2 << INTEL_DP_RESOLUTION_SHIFT_MASK)
>   #define INTEL_DP_RESOLUTION_FAILSAFE	(3 << INTEL_DP_RESOLUTION_SHIFT_MASK)
>   
> +/* PPS T12 Delay Quirk value for eDP */
> +#define T11_T12_800MS		8000
> +
>   struct dp_link_dpll {
>   	int clock;
>   	struct dpll dpll;
> @@ -5230,6 +5233,15 @@ intel_dp_init_panel_power_sequencer(struct drm_device *dev,
>   	intel_pps_dump_state("cur", &cur);
>   
>   	vbt = dev_priv->vbt.edp.pps;
> +	/* Apply the QUIRK_INCREASE_T12_DELAY quirk for a specific
> +	 * type of PCI device to avoid  DP AUX CH Timeouts.
> +	 */
> +	if (dev_priv->quirks & QUIRK_INCREASE_T12_DELAY) {
> +
> +		vbt.t11_t12 = max_t(u16, vbt.t11_t12, T11_T12_800MS);
> +		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,