[PATCH v3 7/9] drm/msm/dpu: drop _dpu_crtc_check_and_setup_lm_bounds from atomic_begin

[Dmitry Baryshkov]

On Wed, 19 Jun 2024 at 01:56, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
> On 6/13/2024 4:20 PM, Abhinav Kumar wrote:
> > On 6/13/2024 3:36 PM, Dmitry Baryshkov wrote:
> >> The dpu_crtc_atomic_check() already calls the function
> >> _dpu_crtc_check_and_setup_lm_bounds().  There is no need to call it
> >> again from dpu_crtc_atomic_begin().
> >>
> >> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> >> ---
> >>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 2 --
> >>   1 file changed, 2 deletions(-)
> >>
> >
> > Reviewed-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
>
>
> This change is causing a small regression on sc7280 chromebook.
>
> I have tested and concluded that this is causing the chrome boot
> animation to disappear.
>
> I have tested a couple of times and without this change it works fine.
>
> If this change was meant as an optimization, can we drop this one and
> investigate later why this is causing one? I have not spent time
> investigating why it happened. Rest of the series works well and I dont
> see any dependency as such. Let me know if that works for you. Otherwise
> I will have to spend a little more time on this patch and why chrome
> compositor does not like this for the animation screen.

Oh, my. Thank you for the test!
I think I know what's happening. The cstate->num_mixers gets set only
in dpu_encoder_virt_atomic_mode_set(). So during
dpu_crtc_atomic_check() we don't have cstate->num_mixers is stale (and
if it is 0, the check is skipped).

I guess I'll have to move cstate->mixers[] and cstate->num_mixers
assignment to the dpu_encoder_virt_atomic_check(). And maybe we should
start thinking about my old idea of moving resource allocation to the
CRTC code.

-- 
With best wishes
Dmitry