[PATCH 5/5] drm/exynos: enable vsync interrupt while waiting for vblank

[Rahul Sharma]

Hi All,

On 18 June 2014 17:04, Rahul Sharma <rahul.sharma at samsung.com> wrote:
> mixer_wait_for_vblank function expects that the upcoming
> vsync interrupt handler routine will clear the
> wait_vsync_event atomic variable.
>
> For this to happen, interrupts should be enabled and
> disabled properly.
>
> Signed-off-by: Rahul Sharma <rahul.sharma at samsung.com>
> ---
>  drivers/gpu/drm/exynos/exynos_mixer.c |    4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
> index 6f18581..7927f2e 100644
> --- a/drivers/gpu/drm/exynos/exynos_mixer.c
> +++ b/drivers/gpu/drm/exynos/exynos_mixer.c
> @@ -1019,6 +1019,8 @@ static void mixer_wait_for_vblank(struct exynos_drm_manager *mgr)
>         }
>         mutex_unlock(&mixer_ctx->mixer_mutex);
>
> +       mixer_enable_vblank(mgr);
> +
>         atomic_set(&mixer_ctx->wait_vsync_event, 1);
>
>         /*
> @@ -1029,6 +1031,8 @@ static void mixer_wait_for_vblank(struct exynos_drm_manager *mgr)
>                                 !atomic_read(&mixer_ctx->wait_vsync_event),
>                                 HZ/20))
>                 DRM_DEBUG_KMS("vblank wait timed out.\n");
> +
> +       mixer_disable_vblank(mgr);
>  }

I found issue with this patch. It is causing deadlock by bypassing
vblank refcounting
and manually disabling the Interrupt.

I switched to following and it is back on track.

drm_vblank_get(mgr->crtc->dev, mixer_ctx->pipe);
drm_vblank_put(mgr->crtc->dev, mixer_ctx->pipe);

I will include this change in next version.

Regards,
Rahul Sharma.

>
>  static void mixer_window_suspend(struct exynos_drm_manager *mgr)
> --
> 1.7.9.5
>