Re: [PATCH] drm/atomic: Check new_crtc_state->active to determine if CRTC needs disable in self refresh mode

[Alex Deucher]

On Wed, Dec 29, 2021 at 11:07 PM Liu Ying <victor.liu@xxxxxxx> wrote:
>
> Actual hardware state of CRTC is controlled by the member 'active' in
> struct drm_crtc_state instead of the member 'enable', according to the
> kernel doc of the member 'enable'.  In fact, the drm client modeset
> and atomic helpers are using the member 'active' to do the control.
>
> Referencing the member 'enable' of new_crtc_state, the function
> crtc_needs_disable() may fail to reflect if CRTC needs disable in
> self refresh mode, e.g., when the framebuffer emulation will be blanked
> through the client modeset helper with the next commit, the member
> 'enable' of new_crtc_state is still true while the member 'active' is
> false, hence the relevant potential encoder and bridges won't be disabled.
>
> So, let's check new_crtc_state->active to determine if CRTC needs disable
> in self refresh mode instead of new_crtc_state->enable.
>
> Fixes: 1452c25b0e60 ("drm: Add helpers to kick off self refresh mode in drivers")
> Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
> Cc: Rob Clark <robdclark@xxxxxxxxxxxx>
> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Cc: Maxime Ripard <mripard@xxxxxxxxxx>
> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxx>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> Signed-off-by: Liu Ying <victor.liu@xxxxxxx>

Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>

Do you need someone to push this for you?

Alex

> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index a7a05e1e26bb..9603193d2fa1 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1016,7 +1016,7 @@ crtc_needs_disable(struct drm_crtc_state *old_state,
>          * it's in self refresh mode and needs to be fully disabled.
>          */
>         return old_state->active ||
> -              (old_state->self_refresh_active && !new_state->enable) ||
> +              (old_state->self_refresh_active && !new_state->active) ||
>                new_state->self_refresh_active;
>  }
>
> --
> 2.25.1
>