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authorDaniel Vetter <daniel.vetter@ffwll.ch>2012-05-22 21:41:25 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2012-05-24 17:54:07 +0200
commitbf2125e2f7e931b50a6c76ba0435ba001409ccbf (patch)
tree1dbd4c96d6a988955d65cad5aa772ac6b53bdf51 /drivers/gpu/drm/i915/intel_tv.c
parent3347111999870c37eab1b969e90af9fdaf0334ba (diff)
drm/i915: wait for a vblank to pass after tv detect
Otherwise the hw will get confused and result in a black screen. This regression has been most likely introduce in commit 974b93315b2213b74a42a87e8a9d4fc8c0dbe90c Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Sun Sep 5 00:44:20 2010 +0100 drm/i915/tv: Poll for DAC state change That commit replace the first msleep(20) with a busy-loop, but failed to keep the 2nd msleep around. Later on we've replaced all these msleep(20) by proper vblanks. For reference also see the commit in xf86-video-intel: commit 1142be53eb8d2ee8a9b60ace5d49f0ba27332275 Author: Jesse Barnes <jbarnes@hobbes.lan> Date: Mon Jun 9 08:52:59 2008 -0700 Fix TV programming: add vblank wait after TV_CTL writes Fxies FDO bug #14000; we need to wait for vblank after writing TV_CTL or following "DPMS on" calls may not actually enable the output. v2: As suggested by Chris Wilson, add a small comment to ensure that no one accidentally removes this vblank wait again - there really seems to be no sane explanation for why we need it, but it is required. Launchpad: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/763688 Reported-and-Tested-by: Robert Lowery <rglowery@exemail.com.au> Cc: Rodrigo Vivi <rodrigo.vivi@gmail.com> Cc: stable@vger.kernel.org Acked-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_tv.c')
-rw-r--r--drivers/gpu/drm/i915/intel_tv.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
index 3346612d295..475f6d4d97f 100644
--- a/drivers/gpu/drm/i915/intel_tv.c
+++ b/drivers/gpu/drm/i915/intel_tv.c
@@ -1194,6 +1194,11 @@ intel_tv_detect_type(struct intel_tv *intel_tv,
I915_WRITE(TV_DAC, save_tv_dac & ~TVDAC_STATE_CHG_EN);
I915_WRITE(TV_CTL, save_tv_ctl);
+ POSTING_READ(TV_CTL);
+
+ /* For unknown reasons the hw barfs if we don't do this vblank wait. */
+ intel_wait_for_vblank(intel_tv->base.base.dev,
+ to_intel_crtc(intel_tv->base.base.crtc)->pipe);
/* Restore interrupt config */
if (connector->polled & DRM_CONNECTOR_POLL_HPD) {