Re: [PATCH 20/35] drm/i915/vrr: Avoid sending PUSH when VRR TG is used with Fixed refresh rate

[Nautiyal, Ankit K]

On 1/25/2025 2:42 AM, Ville Syrjälä wrote:
On Fri, Jan 24, 2025 at 08:30:05PM +0530, Ankit Nautiyal wrote:
As per the spec, the PUSH enable must be set if not configuring for a
fixed refresh rate (i.e Vmin == Flipline == Vmax is not true).

v2: Use helper intel_vrr_use_push(). (Ville)
v3: directly use the condition, instead of checking for VRR mode.

Bspec: 68925
Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
Reviewed-by: Mitul Golani <mitulkumar.ajitkumar.gol...@intel.com> (v1)
---
  drivers/gpu/drm/i915/display/intel_vrr.c | 14 ++++++++++----
  1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c 
b/drivers/gpu/drm/i915/display/intel_vrr.c
index 65bbe40881d6..34e44cd52353 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -437,13 +437,18 @@ void intel_vrr_set_transcoder_timings(const struct 
intel_crtc_state *crtc_state)
                               VRR_VSYNC_START(crtc_state->vrr.vsync_start));
  }
  
+static bool intel_vrr_use_push(const struct intel_crtc_state *crtc_state)
+{
+       return crtc_state->vrr.flipline != crtc_state->vrr.vmax;
+}
+
  void intel_vrr_send_push(struct intel_dsb *dsb,
                         const struct intel_crtc_state *crtc_state)
  {
        struct intel_display *display = to_intel_display(crtc_state);
        enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
  
-	if (!intel_vrrtg_is_enabled(crtc_state))
+       if (!intel_vrr_use_push(crtc_state))
                return;
  
  	if (dsb)
@@ -462,7 +467,7 @@ bool intel_vrr_is_push_sent(const struct intel_crtc_state 
*crtc_state)
        struct intel_display *display = to_intel_display(crtc_state);
        enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
  
-	if (!intel_vrrtg_is_enabled(crtc_state))
+       if (!intel_vrr_use_push(crtc_state))
                return false;
  
  	return intel_de_read(display, TRANS_PUSH(display, cpu_transcoder)) & TRANS_PUSH_SEND;
@@ -476,8 +481,9 @@ void intel_vrr_enable(const struct intel_crtc_state 
*crtc_state)
        if (!intel_vrrtg_is_enabled(crtc_state))
                return;
  
-	intel_de_write(display, TRANS_PUSH(display, cpu_transcoder),
-                      TRANS_PUSH_EN);
+       if (intel_vrr_use_push(crtc_state))
+               intel_de_write(display, TRANS_PUSH(display, cpu_transcoder),
+                              TRANS_PUSH_EN);
What I saw on TGL and ADL is that if you don't enable PUSH then nothing
works. So I think we just want to have this enabled whenever the VRR
timing generator is enabled.


Then perhaps I'll drop this patch, or should we have a specific check 
for TGL/ADL (though we are not enabling fixed refresh rate on these as yet).

Regards,

Ankit

  
  	if (crtc_state->vrr.mode == INTEL_VRRTG_MODE_CMRR) {
                intel_de_write(display, TRANS_VRR_CTL(display, cpu_transcoder),
--
2.45.2