On Fri, Dec 09, 2016 at 12:42:19AM +0200, Laurent Pinchart wrote:
> Hi Daniel,
>
> On Thursday 08 Dec 2016 16:41:04 Daniel Vetter wrote:
> > On Thu, Dec 08, 2016 at 02:45:25PM +0100, Maarten Lankhorst wrote:
> > > Atomic drivers may set properties like rotation on the same fb, which
> > > may require a call to prepare_fb even when framebuffer stays identical.
> > >
> > > Instead of handling all the special cases in the core, let the driver
> > > decide when prepare_fb and cleanup_fb are noops.
> > >
> > > Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> >
> > I think this makes sense, but would be really good to get a pile of acks
> > from driver maintainers on this one. Rob, Eric, Laurent, others?
>
> This is all very nice, but it will introduce at least a performance
> regression, and possibly worse, until drivers get updated. There are 7 drivers
> implementing the .prepare_fb() callback (plus a bunch of drivers that probably
> should use drm_fb_cma_prepare_fb() but don't at the moment). I can't ack this
> patch before they get fixed.
Maarten's commit message is insufficient, since this is defacto a revert
of
commit fcc60b413d14dd06ddbd79ec50e83c4fb2a097ba
Author: Keith Packard <keithp@xxxxxxxxxx>
Date: Sat Jun 4 01:16:22 2016 -0700
drm: Don't prepare or cleanup unchanging frame buffers [v3]
because that breaks stuff. We're simply going back to where we've been a
few months ago. Since this is a regression fix, back to original
behaviour, can you ack (assuming Maarten updates the commit message to
reflect the nature of the commit here)?
-Daniel
>
> > > ---
> > >
> > > drivers/gpu/drm/drm_atomic_helper.c | 9 ---------
> > > 1 file changed, 9 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c
> > > b/drivers/gpu/drm/drm_atomic_helper.c index 23767df72615..d19563651e07
> > > 100644
> > > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > > @@ -1664,9 +1664,6 @@ int drm_atomic_helper_prepare_planes(struct
> > > drm_device *dev,>
> > > funcs = plane->helper_private;
> > >
> > > - if (!drm_atomic_helper_framebuffer_changed(dev, state,
> > > plane_state->crtc)) - continue;
> > > -
> > >
> > > if (funcs->prepare_fb) {
> > >
> > > ret = funcs->prepare_fb(plane, plane_state);
> > > if (ret)
> > >
> > > @@ -1683,9 +1680,6 @@ int drm_atomic_helper_prepare_planes(struct
> > > drm_device *dev,>
> > > if (j >= i)
> > >
> > > continue;
> > >
> > > - if (!drm_atomic_helper_framebuffer_changed(dev, state,
> > > plane_state->crtc)) - continue;
> > > -
> > >
> > > funcs = plane->helper_private;
> > >
> > > if (funcs->cleanup_fb)
> > >
> > > @@ -1952,9 +1946,6 @@ void drm_atomic_helper_cleanup_planes(struct
> > > drm_device *dev,>
> > > for_each_plane_in_state(old_state, plane, plane_state, i) {
> > >
> > > const struct drm_plane_helper_funcs *funcs;
> > >
> > > - if (!drm_atomic_helper_framebuffer_changed(dev, old_state,
> > > plane_state->crtc)) - continue;
> > > -
> > >
> > > funcs = plane->helper_private;
> > >
> > > if (funcs->cleanup_fb)
>
> --
> Regards,
>
> Laurent Pinchart
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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