From: Mario Kleiner <mario.kleiner.de@gmail.com>
To: dri-devel@lists.freedesktop.org
Cc: Dave Airlie <airlied@redhat.com>, Thierry Reding <treding@nvidia.com>
Subject: [PATCH 3/3] drm/tegra: Don't use vblank_disable_immediate on incapable driver.
Date: Tue, 14 Apr 2015 19:41:42 +0200 [thread overview]
Message-ID: <1429033302-16353-3-git-send-email-mario.kleiner.de@gmail.com> (raw)
In-Reply-To: <1429033302-16353-1-git-send-email-mario.kleiner.de@gmail.com>
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 <mario.kleiner.de@gmail.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Dave Airlie <airlied@redhat.com>
---
drivers/gpu/drm/tegra/drm.c | 1 -
1 file changed, 1 deletion(-)
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);
--
1.9.1
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prev parent reply other threads:[~2015-04-14 17:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-14 17:41 [PATCH 1/3] drm: Zero out invalid vblank timestamp in drm_update_vblank_count Mario Kleiner
2015-04-14 17:41 ` [PATCH 2/3] drm: Prevent invalid use of vblank_disable_immediate Mario Kleiner
2015-04-15 7:12 ` Michel Dänzer
2015-04-14 17:41 ` Mario Kleiner [this message]
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