On 27/06/18 23:25, Enric Balletbo i Serra wrote: > From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx> > > This flag tells core to jump ahead the queued update if the conditions > in drm_atomic_async_check() are met. That means we are only able to do an > async update if no modeset is pending and update for the same plane is > not queued. > > It uses the already in place infrastructure for async updates. > > It is useful for cursor updates and async PageFlips over the atomic > ioctl, otherwise in some cases updates may be delayed to the point the > user will notice it. > > DRM_MODE_ATOMIC_ASYNC_UPDATE should be passed to the Atomic IOCTL to use > this feature. > > Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx> > --- > Hi, > > This is an attempt to introduce the new ASYNC_UPDATE flag for atomic > operations, see the commit message for a more detailed description. > > To test this patch we have created an IGT test that we plan to send to > the ML but also was tested using a small program that exercises the uAPI > for easy sanity testing. The program created by Alexandros can be found here > [2]. To test, just build the program and use the --atomic flag to use the > cursor plane in normal (blocking mode), and --atomic-async to use the cursor > plane with the ASYNC_UPDATE flag.E.g. > > drm_cursor --atomic > > or > > drm_cursor --atomic-async > > The test worked on a Samsung Chromebook Plus on top of mainline plus > the patch to update cursors asynchronously through atomic for the > drm/rockchip driver [3]. > > Alexandros also did a proof-of-concept to use this flag and draw cursors > using atomic if possible on ozone [1]. > > Best regards, > Enric > > [1] https://chromium-review.googlesource.com/c/chromium/src/+/1092711 > [2] https://gitlab.collabora.com/alf/drm-cursor > [3] https://patchwork.kernel.org/patch/10492693/ > > > drivers/gpu/drm/drm_atomic.c | 6 ++++++ > drivers/gpu/drm/drm_atomic_helper.c | 9 ++++++--- > include/uapi/drm/drm_mode.h | 4 +++- > 3 files changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c > index c825c76edc1d..15b799f46982 100644 > --- a/drivers/gpu/drm/drm_atomic.c > +++ b/drivers/gpu/drm/drm_atomic.c > @@ -80,6 +80,7 @@ drm_atomic_state_init(struct drm_device *dev, struct drm_atomic_state *state) > * setting this appropriately? > */ > state->allow_modeset = true; > + state->async_update = true; > > state->crtcs = kcalloc(dev->mode_config.num_crtc, > sizeof(*state->crtcs), GFP_KERNEL); > @@ -2320,6 +2321,10 @@ int drm_mode_atomic_ioctl(struct drm_device *dev, > (arg->flags & DRM_MODE_PAGE_FLIP_EVENT)) > return -EINVAL; > > + if ((arg->flags & DRM_MODE_ATOMIC_ALLOW_MODESET) && > + (arg->flags & DRM_MODE_ATOMIC_ASYNC_UPDATE)) > + return -EINVAL; > + > drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE); > > state = drm_atomic_state_alloc(dev); > @@ -2328,6 +2333,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev, > > state->acquire_ctx = &ctx; > state->allow_modeset = !!(arg->flags & DRM_MODE_ATOMIC_ALLOW_MODESET); > + state->async_update = !!(arg->flags & DRM_MODE_ATOMIC_ASYNC_UPDATE); > > retry: > plane_mask = 0; > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index c35654591c12..aeb0523d3bcf 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -891,7 +891,7 @@ int drm_atomic_helper_check(struct drm_device *dev, > if (ret) > return ret; > > - if (state->legacy_cursor_update) > + if (state->async_update || state->legacy_cursor_update) > state->async_update = !drm_atomic_helper_async_check(dev, state); > > return ret; > @@ -1526,13 +1526,16 @@ int drm_atomic_helper_async_check(struct drm_device *dev, > if (new_plane_state->fence) > return -EINVAL; > > + /* Only do an async update if there is a pending commit. */ > + if (!old_plane_state->commit) > + return -EINVAL; > + I noticed that this change triggers a compiler warning, not sure why, but if I add the above lines the compiler (gcc version 7.3.0) shows this warning. drivers/gpu/drm/drm_atomic_helper.c: In function ‘drm_atomic_helper_async_check’: drivers/gpu/drm/drm_atomic_helper.c:1541:9: warning: ‘new_plane_state’ may be used uninitialized in this function [-Wmaybe-uninitialized] return funcs->atomic_async_check(plane, new_plane_state); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/drm_atomic_helper.c:1541:9: warning: ‘plane’ may be used uninitialized in this function [-Wmaybe-uninitialized] Looks a false positive but I'll take a deep look after receive some feedback. Best regards, Enric > /* > * Don't do an async update if there is an outstanding commit modifying > * the plane. This prevents our async update's changes from getting > * overridden by a previous synchronous update's state. > */ > - if (old_plane_state->commit && > - !try_wait_for_completion(&old_plane_state->commit->hw_done)) > + if (!try_wait_for_completion(&old_plane_state->commit->hw_done)) > return -EBUSY; > > return funcs->atomic_async_check(plane, new_plane_state); > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h > index 50bcf4214ff9..772e84f0edeb 100644 > --- a/include/uapi/drm/drm_mode.h > +++ b/include/uapi/drm/drm_mode.h > @@ -718,13 +718,15 @@ struct drm_mode_destroy_dumb { > #define DRM_MODE_ATOMIC_TEST_ONLY 0x0100 > #define DRM_MODE_ATOMIC_NONBLOCK 0x0200 > #define DRM_MODE_ATOMIC_ALLOW_MODESET 0x0400 > +#define DRM_MODE_ATOMIC_ASYNC_UPDATE 0x0800 > > #define DRM_MODE_ATOMIC_FLAGS (\ > DRM_MODE_PAGE_FLIP_EVENT |\ > DRM_MODE_PAGE_FLIP_ASYNC |\ > DRM_MODE_ATOMIC_TEST_ONLY |\ > DRM_MODE_ATOMIC_NONBLOCK |\ > - DRM_MODE_ATOMIC_ALLOW_MODESET) > + DRM_MODE_ATOMIC_ALLOW_MODESET |\ > + DRM_MODE_ATOMIC_ASYNC_UPDATE) > > struct drm_mode_atomic { > __u32 flags; > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
