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drm/i915: Fix deadlock in i830_disable_pipe()

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commit 4488496d58 upstream.

i830_disable_pipe() gets called from the power well code, and thus
we're already holding the power domain mutex. That means we can't
call plane->get_hw_state() as it will also try to grab the
same mutex and will thus deadlock.

Replace the assert_plane() calls (which calls ->get_hw_state()) with
just raw register reads in i830_disable_pipe(). As a bonus we can
now get a warning if plane C is enabled even though we don't even
expose it as a drm plane.

v2: Do a separate WARN_ON() for each plane (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Fixes: d87ce76402 ("drm/i915: Add .get_hw_state() method for planes")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171129125411.29055-1-ville.syrjala@linux.intel.com
(cherry picked from commit 5816d9cbc0)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ville Syrjälä
2017-11-29 14:54:11 +02:00
committed by Greg Kroah-Hartman
parent 50018d0984
commit 050b86b5bf
1 changed files with 5 additions and 2 deletions
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7
drivers/gpu/drm/i915/intel_display.c
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@@ -14717,8 +14717,11 @@ void i830_disable_pipe(struct drm_i915_private *dev_priv, enum pipe pipe)
DRM_DEBUG_KMS("disabling pipe %c due to force quirk\n",
pipe_name(pipe));
assert_planes_disabled(intel_get_crtc_for_pipe(dev_priv, PIPE_A));
assert_planes_disabled(intel_get_crtc_for_pipe(dev_priv, PIPE_B));
WARN_ON(I915_READ(DSPCNTR(PLANE_A)) & DISPLAY_PLANE_ENABLE);
WARN_ON(I915_READ(DSPCNTR(PLANE_B)) & DISPLAY_PLANE_ENABLE);
WARN_ON(I915_READ(DSPCNTR(PLANE_C)) & DISPLAY_PLANE_ENABLE);
WARN_ON(I915_READ(CURCNTR(PIPE_A)) & CURSOR_MODE);
WARN_ON(I915_READ(CURCNTR(PIPE_B)) & CURSOR_MODE);
I915_WRITE(PIPECONF(pipe), 0);
POSTING_READ(PIPECONF(pipe));