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 <[email protected]>
Cc: Madhur Verma <[email protected]>
Cc: Hemanshu Srivastava <[email protected]>
---
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);
--
2.7.4
On Thu, May 03, 2018 at 11:19:32AM +0530, Satendra Singh Thakur wrote:
> 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 <[email protected]>
> Cc: Madhur Verma <[email protected]>
> Cc: Hemanshu Srivastava <[email protected]>
> ---
> 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;
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
> if (plane_state->crtc) {
> crtc_state = drm_atomic_get_crtc_state(plane_state->state,
> plane_state->crtc);
> --
> 2.7.4
>
> _______________________________________________
> dri-devel mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
On Thu, May 03, 2018 at 11:24:59AM +0200, Daniel Vetter wrote:
> On Thu, May 03, 2018 at 11:19:32AM +0530, Satendra Singh Thakur wrote:
> > 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 <[email protected]>
> > Cc: Madhur Verma <[email protected]>
> > Cc: Hemanshu Srivastava <[email protected]>
> > ---
> > 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;
>
> 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?
drm_atomic_set_crtc_for_connector() actually has this since commit
e2d800a3ce1b ("drm: Avoid connector reference imbalance on error path")
--
Ville Syrj?l?
Intel
On Thu, May 03, 2018 at 01:55:03PM +0300, Ville Syrj?l? wrote:
> On Thu, May 03, 2018 at 11:24:59AM +0200, Daniel Vetter wrote:
> > On Thu, May 03, 2018 at 11:19:32AM +0530, Satendra Singh Thakur wrote:
> > > 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 <[email protected]>
> > > Cc: Madhur Verma <[email protected]>
> > > Cc: Hemanshu Srivastava <[email protected]>
> > > ---
> > > 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;
> >
> > 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?
>
> drm_atomic_set_crtc_for_connector() actually has this since commit
> e2d800a3ce1b ("drm: Avoid connector reference imbalance on error path")
Ok, applied for consistency. Thanks for the patch.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch