[PATCH] drm/i915: Always clear INHERIT flag from crtc_state->mode

Sean Paul sean at poorly.run
Mon Oct 15 20:35:17 UTC 2018

From: Sean Paul <seanpaul at chromium.org>

After fastboot/smoothboot completes, we need to fully compute the
state, since a bunch of it is zeroed out. Everything works great if the
first commit from userspace is a modeset, the new mode has no private
flags and we force a modeset (which does the aforementioned

Unfortunately, for non-modeset commits the private_flags in
new_state->mode.private_flags still contains the INHERIT flag. As such,
the state is not computed and we attempt to divide-by-zero in

Cc: stable at vger.kernel.org
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Sean Paul <seanpaul at chromium.org>
 drivers/gpu/drm/i915/intel_atomic.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/intel_atomic.c b/drivers/gpu/drm/i915/intel_atomic.c
index b04952bacf77..1c9a9fee4fb9 100644
--- a/drivers/gpu/drm/i915/intel_atomic.c
+++ b/drivers/gpu/drm/i915/intel_atomic.c
@@ -184,6 +184,7 @@ intel_crtc_duplicate_state(struct drm_crtc *crtc)
 	crtc_state->fifo_changed = false;
 	crtc_state->wm.need_postvbl_update = false;
 	crtc_state->fb_bits = 0;
+	crtc_state->base.mode.private_flags &= ~I915_MODE_FLAG_INHERITED;
 	return &crtc_state->base;
Sean Paul, Software Engineer, Google / Chromium OS

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