[Intel-gfx] [PATCH 2/4] drm/i915/lspcon: Fix resume time initialization due to unasserted HPD

[Sharma, Shashank]

Regards

Shashank


On 1/27/2017 3:09 PM, Imre Deak wrote:
> During system resume time initialization the HPD level on LSPCON ports
> can stay low for an extended amount of time, leading to failed AUX
> transfers and LSPCON initialization. Fix this by waiting for HPD to get
> asserted.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99178
> Cc: Shashank Sharma <shashank.sharma at intel.com>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: <stable at vger.kernel.org> # v4.9+
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>   drivers/gpu/drm/i915/intel_dp.c     | 4 ++--
>   drivers/gpu/drm/i915/intel_drv.h    | 2 ++
>   drivers/gpu/drm/i915/intel_lspcon.c | 5 ++++-
>   3 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index e0f9b9e..a7785ce 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4400,8 +4400,8 @@ static bool bxt_digital_port_connected(struct drm_i915_private *dev_priv,
>    *
>    * Return %true if @port is connected, %false otherwise.
>    */
> -static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> -					 struct intel_digital_port *port)
> +bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> +				  struct intel_digital_port *port)
>   {
>   	if (HAS_PCH_IBX(dev_priv))
>   		return ibx_digital_port_connected(dev_priv, port);
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index b71fece..b9cde11 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1489,6 +1489,8 @@ bool __intel_dp_read_desc(struct intel_dp *intel_dp,
>   bool intel_dp_read_desc(struct intel_dp *intel_dp);
>   int intel_dp_link_required(int pixel_clock, int bpp);
>   int intel_dp_max_data_rate(int max_link_clock, int max_lanes);
> +bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
> +				  struct intel_digital_port *port);
>   
>   /* intel_dp_aux_backlight.c */
>   int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> index f6d4e69..c300647 100644
> --- a/drivers/gpu/drm/i915/intel_lspcon.c
> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
> @@ -158,6 +158,8 @@ static bool lspcon_probe(struct intel_lspcon *lspcon)
>   static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>   {
>   	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
> +	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> +	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
>   	unsigned long start = jiffies;
>   
>   	if (!lspcon->desc_valid)
> @@ -173,7 +175,8 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>   		if (!__intel_dp_read_desc(intel_dp, &desc))
>   			return;
>   
> -		if (!memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
> +		if (intel_digital_port_connected(dev_priv, dig_port) &&
when in PCON mode, live_status is always up for LSPCON port, so this 
check will be always true, isn't it ?
- Shashank
> +		    !memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
>   			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
>   				      jiffies_to_msecs(jiffies - start));
>   			return;