Re: [PATCH v2 2/2] drm/i915/psr: Do not disable Panel Replay if PSR2 is disabled

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

On Wed, Jul 09, 2025 at 10:57:58AM +0300, Jouni Högander wrote:
> Currently disabling PSR2 via enable_psr module parameter causes Panel
> Replay being disabled as well. This patch changes this by still allowing
> Panel Replay even if PSR2 is disabled.
> 
> After this patch enable_psr module parameter values are:
> 
> -1 = PSR1 : yes, PSR2 = yes, Panel Replay : yes
>  0 = PSR1 : no,  PSR2 = no,  Panel Replay : no
>  1 = PSR1 : yes, PSR2 = no,  Panel Replay : yes
>  2 = PSR1 : yes, PSR2 = yes, Panel Replay : no
>  3 = PSR1 : yes, PSR2 = no,  Panel Replay : no
> 
> I.e. values different than -1 and 0 are handled as bitmasks where BIT0
> disables PSR2 and BIT1 disables Panel Replay.
> 
> v2:
>   - make it more clear that enable_psr is bitmask for disabling different
>     PSR modes
> 
> Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
> ---
>  .../drm/i915/display/intel_display_params.c   |  6 ++---
>  drivers/gpu/drm/i915/display/intel_psr.c      | 22 ++++++++++++++-----
>  2 files changed, 19 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c
> index 75316247ee8a..195af19ece5f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_params.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_params.c
> @@ -116,9 +116,9 @@ intel_display_param_named_unsafe(enable_fbc, int, 0400,
>  	"(default: -1 (use per-chip default))");
>  
>  intel_display_param_named_unsafe(enable_psr, int, 0400,
> -	"Enable PSR "
> -	"(0=disabled, 1=enable up to PSR1, 2=enable up to PSR2) "
> -	"Default: -1 (use per-chip default)");
> +	"Enable PSR (0=disabled, 1=disable PSR2 (BIT0), 2=disable Panel Replay (BIT1))."
> +	"Values different from 0 and -1 are handled as bitmask to disable different PSR modes."
> +	"E.g. value 3 disables both PSR2 and Panel Replay. Default: -1 (use per-chip default)");

This thing is very unintuitive. Why don't we just get replace it
with a new disable_psr modparam that is clearly just a bitmask of
what to disable?

>  
>  intel_display_param_named(psr_safest_params, bool, 0400,
>  	"Replace PSR VBT parameters by the safest and not optimal ones. This "
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index a2b5688f0c82..959b868672d0 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -254,13 +254,16 @@ static bool psr2_global_enabled(struct intel_dp *intel_dp)
>  {
>  	struct intel_display *display = to_intel_display(intel_dp);
>  
> +	return display->params.enable_psr == -1 ||
> +		!(display->params.enable_psr & 0x1);
> +}
> +
> +static bool sel_update_global_enabled(struct intel_dp *intel_dp)
> +{
>  	switch (intel_dp->psr.debug & I915_PSR_DEBUG_MODE_MASK) {
> -	case I915_PSR_DEBUG_DISABLE:
>  	case I915_PSR_DEBUG_FORCE_PSR1:
>  		return false;
>  	default:
> -		if (display->params.enable_psr == 1)
> -			return false;
>  		return true;
>  	}
>  }
> @@ -269,7 +272,8 @@ static bool panel_replay_global_enabled(struct intel_dp *intel_dp)
>  {
>  	struct intel_display *display = to_intel_display(intel_dp);
>  
> -	if ((display->params.enable_psr != -1) ||
> +	if ((display->params.enable_psr != -1 &&
> +	     display->params.enable_psr & 0x2) ||
>  	    (intel_dp->psr.debug & I915_PSR_DEBUG_PANEL_REPLAY_DISABLE))
>  		return false;
>  	return true;
> @@ -1415,6 +1419,12 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
>  	if (!intel_dp->psr.sink_psr2_support)
>  		return false;
>  
> +	if (!psr2_global_enabled(intel_dp)) {
> +		drm_dbg_kms(display->drm,
> +			    "PSR2 disabled by flag\n");
> +		return false;
> +	}
> +
>  	/* JSL and EHL only supports eDP 1.3 */
>  	if (display->platform.jasperlake || display->platform.elkhartlake) {
>  		drm_dbg_kms(display->drm, "PSR2 not supported by phy\n");
> @@ -1517,7 +1527,7 @@ static bool intel_sel_update_config_valid(struct intel_dp *intel_dp,
>  		goto unsupported;
>  	}
>  
> -	if (!psr2_global_enabled(intel_dp)) {
> +	if (!sel_update_global_enabled(intel_dp)) {
>  		drm_dbg_kms(display->drm,
>  			    "Selective update disabled by flag\n");
>  		goto unsupported;
> @@ -1664,7 +1674,7 @@ void intel_psr_compute_config(struct intel_dp *intel_dp,
>  	u8 active_pipes = 0;
>  
>  	if (!psr_global_enabled(intel_dp)) {
> -		drm_dbg_kms(display->drm, "PSR disabled by flag\n");
> +		drm_dbg_kms(display->drm, "PSR/Panel Replay disabled by flag\n");
>  		return;
>  	}
>  
> -- 
> 2.43.0

-- 
Ville Syrjälä
Intel