Le 27/09/24 - 16:39, Lyude Paul a écrit :
Currently, there's nothing actually stopping a driver from only registering vblank support for some of it's CRTCs and not for others. As far as I can tell, this isn't really defined behavior on the C side of things - as the documentation explicitly mentions to not use drm_vblank_init() if you don't have vblank support - since DRM then steps in and adds its own vblank emulation implementation.
So, let's fix this edge case and check to make sure it's all or none.
Signed-off-by: Lyude Paul lyude@redhat.com Fixes: 3ed4351a83ca ("drm: Extract drm_vblank.[hc]") Cc: Stefan Agner stefan@agner.ch Cc: Daniel Vetter daniel.vetter@intel.com Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Maxime Ripard mripard@kernel.org Cc: Thomas Zimmermann tzimmermann@suse.de Cc: David Airlie airlied@gmail.com Cc: Simona Vetter simona@ffwll.ch Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v4.13+
drivers/gpu/drm/drm_vblank.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 94e45ed6869d0..4d00937e8ca2e 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -525,9 +525,19 @@ static void drm_vblank_init_release(struct drm_device *dev, void *ptr) */ int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs) {
- struct drm_crtc *crtc; int ret; unsigned int i;
- // Confirm that the required vblank functions have been filled out for all CRTCS
- drm_for_each_crtc(crtc, dev) {
if (!crtc->funcs->enable_vblank || !crtc->funcs->disable_vblank) {drm_err(dev, "CRTC vblank functions not initialized for %s, abort\n",crtc->name);return -EINVAL;}- }
Hi,
I noticed that the kernel bot reported an issue with VKMS and this patch.
I did not take the time to reproduce the issue, but it may come from the fact that VKMS call drm_vblank_init before calling drmm_crtc_init_with_planes [1]. I don't see anything in the documentation that requires the CRTC to be initialized before the vblank, is it a change of the API or an issue in VKMS since 2018 [2]?
Anyway, if this is a requirement, can you explain it in the drm_vblank_init documentation?
Thanks, Louis Chauvet
[1]:https://elixir.bootlin.com/linux/v6.11.2/source/drivers/gpu/drm/vkms/vkms_dr... [2]:https://lore.kernel.org/all/5d9ca7b3884c1995bd4a983b1d2ff1b840eb7f1a.1531402...
spin_lock_init(&dev->vbl_lock); spin_lock_init(&dev->vblank_time_lock);
base-commit: 22512c3ee0f47faab5def71c4453638923c62522
2.46.1