Re: [PATCH] drm/atomic_helper: Add drm_atomic_helper_disable_planes_on_crtc()

On Mon, Nov 23, 2015 at 12:44:35PM +0200, Jyri Sarha wrote:

Add drm_atomic_helper_disable_planes_on_crtc() for disabling all planes associated with the given CRTC. This can be used for instance in the CRTC helper disable callback to disable all planes before shutting down the display pipeline.

Signed-off-by: Jyri Sarha jsarha@ti.com

This a follow version to "[PATCH RFC] drm/crtc_helper: Add drm_crtc_helper_disable_planes()"-patch [1], with Daniel Vetter's review comments [2] implemented. Hope I got everything right this time. Thanks a lot for the prompt review.

When resending a patch please add a revision log to remind reviewers of what you changed. Otherwise they have to dig out the old thread again to figure that out. E.g.

v2 per Daniel's feedback: - Improve kerneldoc. - WARN_ON when atomic_disable is missing. - Also use crtc_funcs->atomic_begin/atomic_flush optionally.

Best regards, Jyri

[1] http://www.spinics.net/lists/dri-devel/msg94720.html [2] http://www.spinics.net/lists/dri-devel/msg94722.html

drivers/gpu/drm/drm_atomic_helper.c | 52 +++++++++++++++++++++++++++++++++++++ include/drm/drm_atomic_helper.h | 2 ++ 2 files changed, 54 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index a53ed7a..229c810 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1281,6 +1281,58 @@ void drm_atomic_helper_commit_planes(struct drm_device *dev, EXPORT_SYMBOL(drm_atomic_helper_commit_planes);

/**

• • drm_atomic_helper_disable_planes_on_crtc - helper to disable CRTC's planes
• • @crtc: CRTC
• • @atomic: if set, synchronize with CRTC's atomic_begin/flush hooks
• • Disables all planes associated with the given CRTC. This can be
• • used for instance in the CRTC helper disable callback to disable
• • all planes before shutting down the display pipeline.
• • If there are planes to disable and the atomic-parameter is set the
• • function calls the CRTC's atomic_begin hook before and atomic_flush
• • hook after disabling the planes.
• • It is a bug to call this function without having implemented the
• • ->atomic_disable() plane hook.
• */

+void drm_atomic_helper_disable_planes_on_crtc(struct drm_crtc *crtc,

• 			      bool atomic)
  

+{

• const struct drm_crtc_helper_funcs *crtc_funcs =

• crtc->helper_private;
  

• struct drm_plane *plane;
• bool flush = false;
• if (!crtc_funcs || !crtc_funcs->atomic_begin)

• atomic = false;
  

• drm_for_each_plane(plane, crtc->dev) {

• const struct drm_plane_helper_funcs *plane_funcs =
  

• 	plane->helper_private;
  

• if (plane->state->crtc != crtc || !plane_funcs)
  

• 	continue;
  

• if (atomic && !flush) {
  

• 	crtc_funcs->atomic_begin(crtc, NULL);
  

• 	flush = true;
  

I think it's clearer if you do that upfront with a simple

if (crtc_funcs->atomic_begin && atomic) crtc_funcs->atomic_begin();

• }
  

• WARN_ON(!plane_funcs->atomic_disable);
  

• if (plane_funcs->atomic_disable)
  

• 	plane_funcs->atomic_disable(plane, NULL);
  

• }
• if (flush) {

• WARN_ON(!crtc_funcs->atomic_flush);
  

• if (crtc_funcs->atomic_flush)
  

• 	crtc_funcs->atomic_flush(crtc, NULL);
  

• }

Same here below. Imo the tracking you do in flush isn't required, since drivers can opt to not implement either atomic_begin or atomic_flush (on some hw you only need atomic_flush, and your code would break such a driver here).

In short the code flow for atomic_begin/flush should look exactly like in drm_atomic_helper_commit_planes_on_crtc, except for the added && atomic check.

Otherwise looks good.

Cheers, Daniel

+} +EXPORT_SYMBOL(drm_atomic_helper_disable_planes_on_crtc);

+/**

• drm_atomic_helper_commit_planes_on_crtc - commit plane state for a crtc
• @old_crtc_state: atomic state object with the old crtc state

diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h index 8cba54a..b7d4237 100644 --- a/include/drm/drm_atomic_helper.h +++ b/include/drm/drm_atomic_helper.h @@ -62,6 +62,8 @@ void drm_atomic_helper_commit_planes(struct drm_device *dev, void drm_atomic_helper_cleanup_planes(struct drm_device *dev, struct drm_atomic_state *old_state); void drm_atomic_helper_commit_planes_on_crtc(struct drm_crtc_state *old_crtc_state); +void drm_atomic_helper_disable_planes_on_crtc(struct drm_crtc *crtc,

• 			      bool atomic);
  
  

void drm_atomic_helper_swap_state(struct drm_device *dev, struct drm_atomic_state *state); -- 1.9.1