xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

drm/atomic: Refcounting for plane_state->fb

Browse Source 
So my original plan was that the drm core refcounts framebuffers like
with the legacy ioctls. But that doesn't work for a bunch of reasons:

- State objects might live longer than until the next fb change
  happens for a plane. For example delayed cleanup work only happens
  _after_ the pageflip ioctl has completed. So this definitely doesn't
  work without the plane state holding its own references.

- The other issue is transition from legacy to atomic implementations,
  where the driver works under a mix of both worlds. Which means
  legacy paths might not properly update the ->fb pointer under
  plane->state->fb. Which is a bit a problem when then someone comes
  around and _does_ try to clean it up when it's long gone.

The second issue is just a bit a transition bug, since drivers should
update plane->state->fb in all the paths that aren't converted yet.
But a bit more robustness for the transition can't hurt - we pull
similar tricks with cleaning up the old fb in the transitional helpers
already.

The pattern for drivers that transition is

	if (plane->state)
		drm_atomic_set_fb_for_plane(plane->state, plane->fb);

inserted after the fb update has logically completed at the end of
->set_config (or ->set_base/mode_set if using the crtc helpers),
->page_flip, ->update_plane or any other entry point which updates
plane->fb.

v2: Update kerneldoc - copypasta fail.

v3: Fix spelling in the commit message (Sean).

Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
This commit is contained in:
Daniel Vetter
2014-11-04 22:57:27 +01:00
parent 3150c7d0c6
commit 321ebf04dc
5 changed files with 60 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
drivers/gpu/drm/drm_atomic_helper.c
View File

@@ -1182,7 +1182,7 @@ retry:
ret = drm_atomic_set_crtc_for_plane(plane_state, crtc);
if (ret != 0)
goto fail;
plane_state->fb = fb;
drm_atomic_set_fb_for_plane(plane_state, fb);
plane_state->crtc_x = crtc_x;
plane_state->crtc_y = crtc_y;
plane_state->crtc_h = crtc_h;
@@ -1250,7 +1250,7 @@ retry:
ret = drm_atomic_set_crtc_for_plane(plane_state, NULL);
if (ret != 0)
goto fail;
plane_state->fb = NULL;
drm_atomic_set_fb_for_plane(plane_state, NULL);
plane_state->crtc_x = 0;
plane_state->crtc_y = 0;
plane_state->crtc_h = 0;
@@ -1422,7 +1422,7 @@ retry:
ret = drm_atomic_set_crtc_for_plane(primary_state, crtc);
if (ret != 0)
goto fail;
primary_state->fb = set->fb;
drm_atomic_set_fb_for_plane(primary_state, set->fb);
primary_state->crtc_x = 0;
primary_state->crtc_y = 0;
primary_state->crtc_h = set->mode->vdisplay;
@@ -1694,7 +1694,7 @@ retry:
ret = drm_atomic_set_crtc_for_plane(plane_state, crtc);
if (ret != 0)
goto fail;
plane_state->fb = fb;
drm_atomic_set_fb_for_plane(plane_state, fb);
ret = drm_atomic_async_commit(state);
if (ret != 0)
@@ -1808,6 +1808,9 @@ EXPORT_SYMBOL(drm_atomic_helper_crtc_destroy_state);
*/
void drm_atomic_helper_plane_reset(struct drm_plane *plane)
{
if (plane->state && plane->state->fb)
drm_framebuffer_unreference(plane->state->fb);
kfree(plane->state);
plane->state = kzalloc(sizeof(*plane->state), GFP_KERNEL);
}
@@ -1823,10 +1826,17 @@ EXPORT_SYMBOL(drm_atomic_helper_plane_reset);
struct drm_plane_state *
drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane)
{
struct drm_plane_state *state;
if (WARN_ON(!plane->state))
return NULL;
return kmemdup(plane->state, sizeof(*plane->state), GFP_KERNEL);
state = kmemdup(plane->state, sizeof(*plane->state), GFP_KERNEL);
if (state && state->fb)
drm_framebuffer_reference(state->fb);
return state;
}
EXPORT_SYMBOL(drm_atomic_helper_plane_duplicate_state);
@@ -1839,8 +1849,11 @@ EXPORT_SYMBOL(drm_atomic_helper_plane_duplicate_state);
* subclassed plane state structure.
*/
void drm_atomic_helper_plane_destroy_state(struct drm_plane *plane,
struct drm_plane_state *state)
struct drm_plane_state *state)
{
if (state->fb)
drm_framebuffer_unreference(state->fb);
kfree(state);
}
EXPORT_SYMBOL(drm_atomic_helper_plane_destroy_state);