Hi all,
This is Ville's vblank rework series, slightly pimped. I've added kerneldoc, some polish and also some additional nasty igt testcases for these crtc on/off vs vblank issues. Seems all to hold together nicely.
Now one thing I wanted to do is roll this out across all drm drivers, but that looks ugly: Many drivers don't support vblanks really, and I couldn't fully audit whether they'd e.g. blow up when userspace tries to use the vblank wait ioctl. But I think we want to have more sanity since otherwise userspace is doomed to carry countless ugly hacks around forever.
The last two patches are my attempt at that. By doing the drm_vblank_on/off dance in the crtc helpers after we know that the crtc is on/off we should have at least a somewhat sane baseline behaviour. Note that since drm_vblank_on/off are idempotent drivers are free to call these functions in their callback at an earlier time, where it makes more sense. But at least it's guaranteed to happen.
Otoh drivers still need to manually complete pageflips, so this doesn't solve all the issues. But until we have a solid cross-driver testsuite for these corner-cases (all the interesting stuff happens when you race vblank waits against concurrent modesets, dpms, or system/runtime suspend/resume) we're pretty much guaranteed to have some that works at best occasionally and is guaranteed to have different behaviour in corner cases. Note that the patches won't degrade behaviour for existing drivers, the drm core changes simply allow us to finally fix things up correctly.
I guess in a way this is a more generic discussion for the drm subsystem at large.
Coments and review highly welcome.
Cheers, Daniel
Daniel Vetter (8): drm/i915: Remove drm_vblank_pre/post_modeset calls drm/doc: Discourage usage of MODESET_CTL ioctl drm/irq: kerneldoc polish drm/irq: Add kms-native crtc interface functions drm/i915: rip our vblank reset hacks for runtime PM drm/i915: Accurately initialize fifo underrun state on gmch platforms [RFC] drm/irq: More robustness in drm_vblank_on|off [RFC] drm/crtc-helper: Enforce sane vblank counter semantics
Peter Hurley (1): drm: Use correct spinlock flavor in drm_vblank_get()
Ville Syrjälä (3): drm: Make the vblank disable timer per-crtc drm: Make blocking vblank wait return when the vblank interrupts get disabled drm: Add drm_vblank_on()
Documentation/DocBook/drm.tmpl | 16 +- drivers/gpu/drm/drm_crtc_helper.c | 12 ++ drivers/gpu/drm/drm_irq.c | 377 ++++++++++++++++++++++++++--------- drivers/gpu/drm/i915/i915_irq.c | 4 +- drivers/gpu/drm/i915/intel_display.c | 36 ++-- drivers/gpu/drm/i915/intel_drv.h | 2 - drivers/gpu/drm/i915/intel_pm.c | 40 ---- include/drm/drmP.h | 10 +- 8 files changed, 341 insertions(+), 156 deletions(-)