[Intel-gfx] [PATCH v2 5/6] drm/i915/vrr: Relocate VRR enable/disable

[Ville Syrjälä]

On Mon, Mar 27, 2023 at 08:05:49PM +0000, Golani, Mitulkumar Ajitkumar wrote:
> Hi Ville,
> 
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville
> > Syrjala
> > Sent: 21 March 2023 19:26
> > To: intel-gfx at lists.freedesktop.org
> > Subject: [Intel-gfx] [PATCH v2 5/6] drm/i915/vrr: Relocate VRR enable/disable
> > 
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > Move VRR enabling/disabling into a place where it also works for fastsets.
> > 
> > With this we always start the transcoder up in non-VRR mode.
> > Granted  we already did that but for a very short period of time. But now
> > that we might end up doing a bit more with the transcoder in non-VRR mode
> > it seems prudent to also update the active timings as the transcoder changes
> > its operating mode.
> > 
> > crtc_state->vrr.enable still tracks whether VRR is actually enabled or not, but
> > now we configure all the other VRR timing registers whenever VRR is possible
> > (whether we actually enable it or not). crtc_state->vrr.flipline can now serve
> > as our "is VRR possible" bit of state.
> 
> Understood the change. I was thinking if it is possible to make distinguish between
> is VRR "possible" and is VRR "enabled" by adding a new param ? Although changes looks
> good to me but using Flipline value as "is VRR Possible" makes it bit confusing.

I suppose we could think about adding a knob for it. It would just
reflect the flipline enable bit state in the current scheme.

Another thing I was pondering is whether we should even care about
this in intel_dp_prepare_link_train() or if we should just set the
MSA ingore bit any time we have a VRR capable display. But I suppose
that could have some implicatations eg. for interlaces displays modes.

-- 
Ville Syrjälä
Intel