Op 15-10-18 om 19:05 schreef Rodrigo Siqueira: > For historical reason, the function drm_wait_vblank_ioctl always return > -EINVAL if something gets wrong. This scenario limits the flexibility > for the userspace make detailed verification of the problem and take > some action. In particular, the validation of “if (!dev->irq_enabled)” > in the drm_wait_vblank_ioctl is responsible for checking if the driver > support vblank or not. If the driver does not support VBlank, the > function drm_wait_vblank_ioctl returns EINVAL which does not represent > the real issue; this patch changes this behavior by return EOPNOTSUPP. > Additionally, some operations are unsupported by this function, and > returns EINVAL; this patch also changes the return value to EOPNOTSUPP > in this case. Lastly, the function drm_wait_vblank_ioctl is invoked by > libdrm, which is used by many compositors; because of this, it is > important to check if this change breaks any compositor. In this sense, > the following projects were examined: > > * Drm-hwcomposer > * Kwin > * Sway > * Wlroots > * Wayland-core > * Weston > * Xorg (67 different drivers) > > For each repository the verification happened in three steps: > > * Update the main branch > * Look for any occurrence "drmWaitVBlank" with the command: > git grep -n "drmWaitVBlank" > * Look in the git history of the project with the command: > git log -SdrmWaitVBlank > > Finally, none of the above projects validate the use of EINVAL which > make safe, at least for these projects, to change the return values. > > Change since V1: > Daniel Vetter and Chris Wilson > - Replace ENOTTY by EOPNOTSUPP > - Return EINVAL if the parameters are wrong > > Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@xxxxxxxxx> > --- > drivers/gpu/drm/drm_vblank.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c > index 98e091175921..80f5a3bb427e 100644 > --- a/drivers/gpu/drm/drm_vblank.c > +++ b/drivers/gpu/drm/drm_vblank.c > @@ -1533,10 +1533,10 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, > unsigned int flags, pipe, high_pipe; > > if (!dev->irq_enabled) > - return -EINVAL; > + return -EOPNOTSUPP; Change to -EIO? If userspace would ever print this out, it would print the following confusing message to userspace: "Operation not supported on transport endpoint" > > if (vblwait->request.type & _DRM_VBLANK_SIGNAL) > - return -EINVAL; > + return -EOPNOTSUPP; I would keep this -EINVAL, tbh and making it part of the below if statement.. > if (vblwait->request.type & > ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | Cheers, Maarten _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
