> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Ville
> Syrjala
> Sent: Thursday, December 16, 2021 1:08 PM
> To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Subject: [PATCH] drm/i915/fbc: Remember to update FBC state even
> when not reallocating CFB
>
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> We mustn't forget to update our FBC state even if we don't have to reallocate
> the CFB. Otherwise we won't refresh our notion of what eg. the new fence or
> the new override CFB stride should be. Using the wrong CFB stride in particular
> can cause underruns and could even corrupt other stuff in stolen.
>
> Fixes: f4cfdbb02ca8 ("drm/i915/fbc: Nuke state_cache")
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4774
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Reviewed-by: Mika Kahola <mika.kahola@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_fbc.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c
> b/drivers/gpu/drm/i915/display/intel_fbc.c
> index 987ea4c4b5d0..465dc4e97ea8 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -1408,8 +1408,10 @@ static void __intel_fbc_enable(struct
> intel_atomic_state *state,
> if (fbc->state.plane != plane)
> return;
>
> - if (intel_fbc_is_ok(plane_state))
> + if (intel_fbc_is_ok(plane_state)) {
> + intel_fbc_update_state(state, crtc, plane);
> return;
> + }
>
> __intel_fbc_disable(fbc);
> }
> --
> 2.32.0
