drm/i915: Assert that the transcoder is indeed off before modifying it
Inspired by a recent regression that seems to confuse pch transcoder
state, let's be a bit more paranoid.
References: https://bugs.freedesktop.org/show_bug.cgi?id=49712
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Pimped commit message.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 1a06f97..391439f 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2782,6 +2782,8 @@
int pipe = intel_crtc->pipe;
u32 reg, temp;
+ assert_transcoder_disabled(dev_priv, pipe);
+
/* For PCH output, training FDI link */
dev_priv->display.fdi_link_train(crtc);