Re: [PATCH v11 05/11] drm/i915/vrr: Prepare to Use TRANS_PUSH mechanism for PSR frame change

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 1/27/2026 6:11 PM, Jouni Högander wrote:
> On Lunarlake and onward it is possible to generate PSR Frame Change
> event using TRANS_PUSH mechanism:
>
> Ensure push is performed on flip if needed by PSR.
>
> Don't use intel_psr_trigger_frame_change_event if PSR uses trans push as
> Frame Change event: When not using trans push to generate Frame Change
> event plane/pipe register writes are triggering the event. This is causing
> problems when transiting to PSR active/idle and the event is coming in. To
> tackle this we are waiting PSR to idle and using
> intel_psr_trigger_frame_change_event to ensure PSR exit. If the Frame
> change event is triggered after everything is configured (on trans push) we
> don't need to worry about all this.
>
> Ensure possible intel_vrr_tg_disable call is not overwriting
> LNL_TRANS_PUSH_PSR_PR_EN.
>
> v8:
>    - split adding intel_vrr_psr_frame_change_enable as a separate change
>    - update commit message
> v7:
>    - HAS_PSR_FRAME_CHANGE macro moved to separate patch and renamed as
>      HAS_PSR_TRANS_PUSH_FRAME_CHANGE
>    - use intel_psr_use_trans_push instead of HAS_PSR_FRAME_CHANGE in
>      intel_psr_trigger_frame_change
>    - moved calling intel_vrr_psr_frame_change_enable away from this patch
> v6:
>    - add HAS_PSR_FRAME_CHANGE macro
>    - use TRANS_PUSH in instead of TRAN_VRR_CTL
> v5: use intel_psr_use_trans_push for intel_vrr_psr_frame_change_enable
> v4:
>    - use rmw when enabling/disabling transcoder
>    - set TRANS_PUSH_EN conditionally in intel_vrr_send_push
>    - do not call intel_vrr_send_push from intel_psr_trigger_frame_change
>    - do not enable using TRANS_PUSH mechanism for PSR "Frame Change"
> v3:
>    - use rmw when enabling/disabling
>    - keep LNL_TRANS_PUSH_PSR_PR_EN set always on LunarLake and onwards
> v2: use intel_vrr_trans_push_enabled_set_clear instead of rmw
>
> Signed-off-by: Jouni Högander <jouni.hogander@intel.com>

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>


> ---
>   drivers/gpu/drm/i915/display/intel_crtc.c | 4 +++-
>   drivers/gpu/drm/i915/display/intel_psr.c  | 8 +++++---
>   drivers/gpu/drm/i915/display/intel_vrr.c  | 5 +++--
>   3 files changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c
> index 778ebc5095c3..ed3c6c4ce025 100644
> --- a/drivers/gpu/drm/i915/display/intel_crtc.c
> +++ b/drivers/gpu/drm/i915/display/intel_crtc.c
> @@ -747,7 +747,9 @@ void intel_pipe_update_end(struct intel_atomic_state *state,
>   	 * which would cause the next frame to terminate already at vmin
>   	 * vblank start instead of vmax vblank start.
>   	 */
> -	if (!state->base.legacy_cursor_update)
> +	if (!state->base.legacy_cursor_update ||
> +	    (intel_psr_use_trans_push(new_crtc_state) &&
> +	     !new_crtc_state->vrr.enable))
>   		intel_vrr_send_push(NULL, new_crtc_state);
>   
>   	local_irq_enable();
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index b0d72c04db45..9613c50623dc 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -2516,9 +2516,11 @@ void intel_psr_trigger_frame_change_event(struct intel_dsb *dsb,
>   		intel_pre_commit_crtc_state(state, crtc);
>   	struct intel_display *display = to_intel_display(crtc);
>   
> -	if (crtc_state->has_psr)
> -		intel_de_write_dsb(display, dsb,
> -				   CURSURFLIVE(display, crtc->pipe), 0);
> +	if (!crtc_state->has_psr || intel_psr_use_trans_push(crtc_state))
> +		return;
> +
> +	intel_de_write_dsb(display, dsb,
> +			   CURSURFLIVE(display, crtc->pipe), 0);
>   }
>   
>   /**
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 66c68e7f3a49..8a072f90049f 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -698,7 +698,7 @@ void intel_vrr_send_push(struct intel_dsb *dsb,
>   	struct intel_display *display = to_intel_display(crtc_state);
>   	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
>   
> -	if (!crtc_state->vrr.enable)
> +	if (!crtc_state->vrr.enable && !intel_psr_use_trans_push(crtc_state))
>   		return;
>   
>   	if (dsb)
> @@ -920,7 +920,8 @@ static void intel_vrr_tg_disable(const struct intel_crtc_state *old_crtc_state)
>   				       VRR_STATUS_VRR_EN_LIVE, 1000))
>   		drm_err(display->drm, "Timed out waiting for VRR live status to clear\n");
>   
> -	intel_de_write(display, TRANS_PUSH(display, cpu_transcoder), 0);
> +	intel_de_rmw(display, TRANS_PUSH(display, cpu_transcoder),
> +		     TRANS_PUSH_EN, 0);
>   }
>   
>   void intel_vrr_enable(const struct intel_crtc_state *crtc_state)