In the func drm_atomic_set_crtc_for_plane, with the current code, if crtc of the plane_state and crtc passed as argument to the func are same, entire func will executed in vein. It will get state of crtc and clear and set the bits in plane_mask. All these steps are not required for same old crtc. Ideally, we should do nothing in this case, this patch handles the same, and causes the program to return without doing anything in such scenario.
Signed-off-by: Satendra Singh Thakur satendra.t@samsung.com Cc: Madhur Verma madhur.verma@samsung.com Cc: Hemanshu Srivastava hemanshu.s@samsung.com --- drivers/gpu/drm/drm_atomic.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index 7d25c42..5bd3365 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -1421,7 +1421,9 @@ drm_atomic_set_crtc_for_plane(struct drm_plane_state *plane_state, { struct drm_plane *plane = plane_state->plane; struct drm_crtc_state *crtc_state; - + /* Nothing to do for same crtc*/ + if (plane_state->crtc == crtc) + return 0; if (plane_state->crtc) { crtc_state = drm_atomic_get_crtc_state(plane_state->state, plane_state->crtc);
On Thu, May 03, 2018 at 11:19:32AM +0530, Satendra Singh Thakur wrote:
I didn't do this (both here and in the set_crtc_for_connector functions) because the overhead is probably way down in the noise compared to the overall atomic commit machinery. Do you really see this as a hotpath? -Daniel
On Thu, May 03, 2018 at 01:55:03PM +0300, Ville Syrjälä wrote:
Ok, applied for consistency. Thanks for the patch. -Daniel
dri-devel@lists.freedesktop.org
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Daniel Vetter -
Satendra Singh Thakur -
Ville Syrjälä