[Intel-gfx] [PATCH v4 8/9] drm/i915/psr: Set idle frames to maximum while getting pipe CRC

[Dhinakaran Pandiyan]

On Fri, 2019-03-01 at 17:34 -0800, José Roberto de Souza wrote:
> Increase the idle frames to activate PSR1 to avoid CRC timeouts, as
> soon as pipe CRC is enabled it will avoid PSR1 to activate but if
> PSR1 is activate before that, hardware goes to lower power states
> that inhibits CRC calculations causing CRC timeout errors in IGT
> tests.
> 
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h  |  1 +
>  drivers/gpu/drm/i915/intel_psr.c | 17 +++++++++++++++--
>  2 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h
> b/drivers/gpu/drm/i915/i915_drv.h
> index 453af7438e67..e336f758e481 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -521,6 +521,7 @@ struct i915_psr {
>  	bool sink_not_reliable;
>  	bool irq_aux_error;
>  	u16 su_x_granularity;
> +	bool crc_enabled;
>  };
>  
>  enum intel_pch {
> diff --git a/drivers/gpu/drm/i915/intel_psr.c
> b/drivers/gpu/drm/i915/intel_psr.c
> index d3e3996551c6..b237d96db277 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -452,6 +452,16 @@ static void hsw_activate_psr1(struct intel_dp
> *intel_dp)
>  	 * frames, we'll go with 9 frames for now
>  	 */
>  	idle_frames = max(idle_frames, dev_priv->psr.sink_sync_latency
> + 1);
> +
> +	/*
> +	 * Increase the idle frames to active PSR1 to avoid CRC
> timeouts, as
> +	 * soon as pipe CRC is enabled it will avoid PSR1 to activate
> but if
> +	 * PSR1 is activate before that, hardware goes to lower power
> states
> +	 * that inhibits CRC calculations.
> +	 */
> +	if (dev_priv->psr.crc_enabled)
> +		idle_frames = 0xf;

My understanding was only the enable bit can be changed when PSR is
enabled. Does this work?

> +
>  	val |= idle_frames << EDP_PSR_IDLE_FRAME_SHIFT;