[PATCH v2 7/7] drm/mediatek: Fix mtk_atomic_complete for runtime_pm

Daniel Vetter
2016-08-04T10:42:23Z

On Thu, Aug 04, 2016 at 10:59:57AM +0800, Bibby Hsieh wrote:
> To properly implement atomic w/ runtime pm, we move
> drm_atomic_helper_commit_modeset_enables() above
> drm_atomic_helper_commit_planes() to ensure CRTCs are enabled before
> modifying plane registers, and set active_only to true to filter out
> plane update notifications when the CRTC is disabled.
>
> According to the document from linux kernel:
> Set the active_only parameters to true in order not to receive plane
> update notifications related to a disabled CRTC. This avoids the need
> to manually ignore plane updates in driver code when the driver and/or
> hardware can't or just don't need to deal with updates on disabled
> CRTCs, for example when supporting runtime PM.
>
> Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
> Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>

btw if you want to clean up some more code, would be neat to switch
mediatek to the generic nonblocking support in the atomic helpers instead
of rolling your own.
-Daniel

> ---
> drivers/gpu/drm/mediatek/mtk_drm_drv.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index b1223d5..507392a 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -61,10 +61,25 @@ static void mtk_atomic_complete(struct mtk_drm_private *private,
>
> mtk_atomic_wait_for_fences(state);
>
> + /*
> + * Mediatek drm supports runtime PM, so plane registers cannot be
> + * written when their crtc is disabled.
> + *
> + * The comment for drm_atomic_helper_commit states:
> + * For drivers supporting runtime PM the recommended sequence is
> + *
> + * drm_atomic_helper_commit_modeset_disables(dev, state);
> + * drm_atomic_helper_commit_modeset_enables(dev, state);
> + * drm_atomic_helper_commit_planes(dev, state, true);
> + *
> + * See the kerneldoc entries for these three functions for more details.
> + */
> drm_atomic_helper_commit_modeset_disables(drm, state);
> - drm_atomic_helper_commit_planes(drm, state, false);
> drm_atomic_helper_commit_modeset_enables(drm, state);
> + drm_atomic_helper_commit_planes(drm, state, true);
> +
> drm_atomic_helper_wait_for_vblanks(drm, state);
> +
> drm_atomic_helper_cleanup_planes(drm, state);
> drm_atomic_state_free(state);
> }
> --
> 1.7.9.5
>

--
Daniel Vetter
Software Engineer, Intel Corporation