With the prep patch to encapsulate ->set_crtc calls, this is now
rather easy. Hooray for inconsistent semantics between ->set_crtc and
->page_flip, where the driver callback is supposed to update the fb
pointer, and ->update_plane, where the drm core does the same.
Also, since the drm core functions check crtc->fb before calling into
driver callbacks, we can't really reduce the critical sections
protected by the mode_config locks.
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
drivers/gpu/drm/drm_crtc.c | 37 ++++++++++++++++++++++++++++++-------
1 file changed, 30 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 229853e..6562eba 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1983,8 +1983,21 @@ out:
int drm_mode_set_config_internal(struct drm_mode_set *set)
{
struct drm_crtc *crtc = set->crtc;
+ struct drm_framebuffer *fb, *old_fb;
+ int ret;
+
+ old_fb = crtc->fb;
+ fb = set->fb;
- return crtc->funcs->set_config(set);
+ ret = crtc->funcs->set_config(set);
+ if (ret == 0) {
+ if (old_fb)
+ drm_framebuffer_unreference(old_fb);
+ if (fb)
+ drm_framebuffer_reference(fb);
+ }
+
+ return ret;
}
EXPORT_SYMBOL(drm_mode_set_config_internal);
@@ -2045,6 +2058,8 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
goto out;
}
fb = crtc->fb;
+ /* Make refcounting symmetric with the lookup path. */
+ drm_framebuffer_reference(fb);
} else {
fb = drm_framebuffer_lookup(dev, crtc_req->fb_id);
if (!fb) {
@@ -2053,9 +2068,6 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
ret = -EINVAL;
goto out;
}
- /* fb is protect by the mode_config lock, so drop the
- * ref immediately */
- drm_framebuffer_unreference(fb);
}
mode = drm_mode_create(dev);
@@ -2155,6 +2167,9 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
ret = drm_mode_set_config_internal(&set);
out:
+ if (fb)
+ drm_framebuffer_unreference(fb);
+
kfree(connector_set);
drm_mode_destroy(dev, mode);
drm_modeset_unlock_all(dev);
@@ -3673,7 +3688,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
struct drm_mode_crtc_page_flip *page_flip = data;
struct drm_mode_object *obj;
struct drm_crtc *crtc;
- struct drm_framebuffer *fb;
+ struct drm_framebuffer *fb = NULL, *old_fb = NULL;
struct drm_pending_vblank_event *e = NULL;
unsigned long flags;
int hdisplay, vdisplay;
@@ -3704,8 +3719,6 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
fb = drm_framebuffer_lookup(dev, page_flip->fb_id);
if (!fb)
goto out;
- /* fb is protect by the mode_config lock, so drop the ref immediately */
- drm_framebuffer_unreference(fb);
hdisplay = crtc->mode.hdisplay;
vdisplay = crtc->mode.vdisplay;
@@ -3751,6 +3764,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
(void (*) (struct drm_pending_event *)) kfree;
}
+ old_fb = crtc->fb;
ret = crtc->funcs->page_flip(crtc, fb, e);
if (ret) {
if (page_flip->flags & DRM_MODE_PAGE_FLIP_EVENT) {
@@ -3759,9 +3773,18 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
spin_unlock_irqrestore(&dev->event_lock, flags);
kfree(e);
}
+ /* Keep the old fb, don't unref it. */
+ old_fb = NULL;
+ } else {
+ /* Unref only the old framebuffer. */
+ fb = NULL;
}
out:
+ if (fb)
+ drm_framebuffer_unreference(fb);
+ if (old_fb)
+ drm_framebuffer_unreference(old_fb);
drm_modeset_unlock_all(dev);
return ret;
}
--
1.7.10.4
