Op 01-02-18 om 08:08 schreef Oleksandr Andrushchenko: > Hi, all! > > I am working on a para-virtualized frontend DRM driver for Xen [1] > which implements display device I/O interface for Xen guest OSes [2]. > > At the moment I am rebasing the existing implementation from 4.9 kernel > to recent and found that when user-space DRM application exits then CRTC's > .set_config callback is not called to reset CRTC's mode to NULL. > > I tracked the change down to commit 846c7dfc1193eb2f9866fe2fa0ae7d45c72f95b9 > "drm/atomic: Try to preserve the crtc enabled state in drm_atomic_remove_fb, > v2. > > This introduces a slight behavioral change to rmfb. Instead of > disabling a crtc when the primary plane is disabled, we try to > preserve it. > <snip> > If the atomic commit is rejected by the driver then we will still > fall back to the old behavior and turn off the crtc. > " > which per my understanding is ok for real hardware, but in my case I still > need .set_config to be called with NULL: this way I can tell the backend > > driver that it can release resources for this connection on its end. > > > I tried to implement drm_mode_config_funcs's .atomic_commit returning -EINVAL > on tear down, but at best it made CRTC's atomic state change to NOCRTC, but > still no .set_config callback seen. > > Can anyone please tell me the right sequence to implement old remove FB > behavior for atomic drivers? Or what could be the problem on my side?
rmfb was never meant to mean that the crtc will be disabled as well. vmwgfx relied on that behavior as well for old userspace support because userspace never called set_config. If you're an atomic driver, the driver core will never call set_config any more, even if the first attempt to disable returns -EINVAL. Even the fbcon helpers now perform direct calls to atomic_commit(). If you then still want to revert to old behavior and it doesn't make sense to have the crtc enabled without primary plane enabled, you can copy the check from drm_simple_kms_crtc_check(). ~Maarten _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
