From: Mario Kleiner Date: Mon, 4 May 2015 04:29:44 +0000 (+0200) Subject: drm/tegra: Don't use vblank_disable_immediate on incapable driver. X-Git-Tag: v4.1~156^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3790e395b8f4b66fe4e53629f304505c110a2be7;p=platform%2Fkernel%2Flinux-amlogic.git drm/tegra: Don't use vblank_disable_immediate on incapable driver. Tegra would not only need a hardware vblank counter that increments at leading edge of vblank, but also support for instantaneous high precision vblank timestamp queries, ie. a proper implementation of dev->driver->get_vblank_timestamp(). Without these, there can be off-by-one errors during vblank disable/enable if the scanout is inside vblank at en/disable time, and additionally clients will never see any useable vblank timestamps when querying via drmWaitVblank ioctl. This would negatively affect swap scheduling under X11 and Wayland. Signed-off-by: Mario Kleiner Acked-by: Thierry Reding Signed-off-by: Dave Airlie --- diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c index 1833abd..bfad15a 100644 --- a/drivers/gpu/drm/tegra/drm.c +++ b/drivers/gpu/drm/tegra/drm.c @@ -173,7 +173,6 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags) drm->irq_enabled = true; /* syncpoints are used for full 32-bit hardware VBLANK counters */ - drm->vblank_disable_immediate = true; drm->max_vblank_count = 0xffffffff; err = drm_vblank_init(drm, drm->mode_config.num_crtc);