Re: [Intel-gfx] [PATCH] drm/i915/lnl: Remove watchdog timers for PSR

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

On Fri, Oct 06, 2023 at 02:42:10PM +0300, Mika Kahola wrote:
> Currently we are not using watchdog timers for PSR/PSR2.
> The patch disables these timers so they are not in use.

I can't figure out what you're saying here. What bspec seems to be
saying is that the max_sleep thing got nuked from the hw so we no
longer need to mask it.

> 
> BSpec: 69895
> 
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_psr.c | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 850b11f20285..13b58dceb2bf 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -672,11 +672,15 @@ static void hsw_activate_psr1(struct intel_dp *intel_dp)
>  	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>  	enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
>  	u32 max_sleep_time = 0x1f;
> -	u32 val = EDP_PSR_ENABLE;
> +	u32 val = 0;
>  
> -	val |= EDP_PSR_IDLE_FRAMES(psr_compute_idle_frames(intel_dp));
>  
> -	val |= EDP_PSR_MAX_SLEEP_TIME(max_sleep_time);
> +	if (DISPLAY_VER(dev_priv) < 20) {
> +		val =  EDP_PSR_ENABLE;

That would mean you never enable PSR1 on lnl+

> +		val |= EDP_PSR_MAX_SLEEP_TIME(max_sleep_time);
> +	}
> +
> +	val |= EDP_PSR_IDLE_FRAMES(psr_compute_idle_frames(intel_dp));
>  	if (IS_HASWELL(dev_priv))
>  		val |= EDP_PSR_MIN_LINK_ENTRY_TIME_8_LINES;
>  
> @@ -1398,10 +1402,16 @@ static void intel_psr_enable_source(struct intel_dp *intel_dp,
>  	 * runtime_pm besides preventing  other hw tracking issues now we
>  	 * can rely on frontbuffer tracking.
>  	 */
> -	mask = EDP_PSR_DEBUG_MASK_MEMUP |
> -	       EDP_PSR_DEBUG_MASK_HPD |
> -	       EDP_PSR_DEBUG_MASK_LPSP |
> -	       EDP_PSR_DEBUG_MASK_MAX_SLEEP;
> +	if (DISPLAY_VER(dev_priv) >= 20)
> +		mask = EDP_PSR_DEBUG_MASK_MEMUP |
> +		       EDP_PSR_DEBUG_MASK_HPD |
> +		       EDP_PSR_DEBUG_MASK_LPSP;
> +	else
> +		mask = EDP_PSR_DEBUG_MASK_MEMUP |
> +		       EDP_PSR_DEBUG_MASK_HPD |
> +		       EDP_PSR_DEBUG_MASK_LPSP |
> +		       EDP_PSR_DEBUG_MASK_MAX_SLEEP;

The hpd mask bit also seems gone now, though there is no explanation
why it disappeared.

> +
>  
>  	/*
>  	 * No separate pipe reg write mask on hsw/bdw, so have to unmask all
> -- 
> 2.34.1

-- 
Ville Syrjälä
Intel