Re: [PATCH 12/19] drm/i915/psr: Write the PR config DPCDs in burst mode

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

On Wed, Mar 11, 2026 at 05:06:04PM +0530, Ankit Nautiyal wrote:
> Replace the consecutive single-byte writes to PANEL_REPLAY_CONFIG and
> CONFIG2 with one drm_dp_dpcd_write() burst starting at PANEL_REPLAY_CONFIG,
> reducing AUX transactions.
> 
> Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_psr.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 5041a5a138d1..ee6e26abd05e 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -774,27 +774,33 @@ static bool psr2_su_region_et_valid(struct intel_connector *connector, bool pane
>  static void _panel_replay_enable_sink(struct intel_dp *intel_dp,
>  				      const struct intel_crtc_state *crtc_state)
>  {
> -	u8 val = DP_PANEL_REPLAY_ENABLE |
> +	struct intel_display *display = to_intel_display(intel_dp);
> +	u8 panel_replay_config = DP_PANEL_REPLAY_ENABLE |
>  		DP_PANEL_REPLAY_VSC_SDP_CRC_EN |
>  		DP_PANEL_REPLAY_UNRECOVERABLE_ERROR_EN |
>  		DP_PANEL_REPLAY_RFB_STORAGE_ERROR_EN |
>  		DP_PANEL_REPLAY_ACTIVE_FRAME_CRC_ERROR_EN;
>  	u8 panel_replay_config2 = DP_PANEL_REPLAY_CRC_VERIFICATION;
> +	u8 buf[2];

u8 panel_replay_config[2];

would reduce the number of variables we have to contend with.

> +	int ret;
>  
>  	if (crtc_state->has_sel_update)
> -		val |= DP_PANEL_REPLAY_SU_ENABLE;
> +		panel_replay_config |= DP_PANEL_REPLAY_SU_ENABLE;
>  
>  	if (crtc_state->enable_psr2_su_region_et)
> -		val |= DP_PANEL_REPLAY_ENABLE_SU_REGION_ET;
> +		panel_replay_config |= DP_PANEL_REPLAY_ENABLE_SU_REGION_ET;
>  
>  	if (crtc_state->req_psr2_sdp_prior_scanline)
>  		panel_replay_config2 |=
>  			DP_PANEL_REPLAY_SU_REGION_SCANLINE_CAPTURE;
>  
> -	drm_dp_dpcd_writeb(&intel_dp->aux, PANEL_REPLAY_CONFIG, val);
> +	buf[0] = panel_replay_config;
> +	buf[1] = panel_replay_config2;
> +
> +	ret = drm_dp_dpcd_write(&intel_dp->aux, PANEL_REPLAY_CONFIG, buf, sizeof(buf));
>  
> -	drm_dp_dpcd_writeb(&intel_dp->aux, PANEL_REPLAY_CONFIG2,
> -			   panel_replay_config2);
> +	if (ret < 0 || ret != sizeof(buf))

The < 0 check is redunadnt.

> +		drm_dbg_kms(display->drm, "Failed to write Panel Replay Configs\n");
>  }
>  
>  static void _psr_enable_sink(struct intel_dp *intel_dp,
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel