[Intel-gfx] [PATCH] drm/i915: Don't do pre plane update on disabled crtcs

Mika Kuoppala mika.kuoppala at linux.intel.com
Thu Jan 14 08:32:10 PST 2016

CI/Bat got following (shortened) trace on byt and also
on bsw:

------------[ cut here ]-----------
Unclaimed register detected before reading register 0x186500
Call Trace:
 __unclaimed_reg_debug+0x68/0x80 [i915]
vlv_read32+0x2de/0x370 [i915]
intel_set_memory_cxsr+0x87/0x1a0 [i915]
intel_pre_plane_update+0xb3/0xf0 [i915]
intel_atomic_commit+0x3b5/0x17c0 [i915]
---[ end trace 6387a0ad001bb39f ]---

Fix this by limiting pre plane update only to active crtcs.

References: https://bugs.freedesktop.org/show_bug.cgi?id=93698
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
 drivers/gpu/drm/i915/intel_display.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index aa24f79d85bf..a134a698d97d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13580,9 +13580,8 @@ static int intel_atomic_commit(struct drm_device *dev,
 		if (!needs_modeset(crtc->state))
-		intel_pre_plane_update(intel_crtc);
 		if (crtc_state->active) {
+			intel_pre_plane_update(intel_crtc);
 			intel_crtc_disable_planes(crtc, crtc_state->plane_mask);
 			intel_crtc->active = false;

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