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Commit 0368920e authored by Chris Wilson's avatar Chris Wilson Committed by Jani Nikula
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drm/i915: Disable FBC by default also on Haswell and later 

It causes black screen on bootup and is approximately 100x slower than
running with FBC disabled, so the GPU runs at a high frequency for much
longer - completely contrary to the power saving claims. It also still
has mutex deadlocks in multi-head scenarios, which can lead to a
system/X lockup. These bugs were known before FBC was enabled by default
on Haswell and still have not been fixed.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79716


Reported-and-tested-by: default avatarJon Kristensen <info@jonkri.com>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
[Jani: update subject to reflect the actual change]
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent bc1dfff0

drivers/gpu/drm/i915/intel_pm.c

+1 −2
Original line number Diff line number Diff line
@@ -511,8 +511,7 @@ void intel_update_fbc(struct drm_device *dev) 
	obj = intel_fb->obj;

	adjusted_mode = &intel_crtc->config.adjusted_mode;



	if (i915.enable_fbc < 0 &&

	    INTEL_INFO(dev)->gen <= 7 && !IS_HASWELL(dev)) {

	if (i915.enable_fbc < 0) {

		if (set_no_fbc_reason(dev_priv, FBC_CHIP_DEFAULT))

			DRM_DEBUG_KMS("disabled per chip default\n");

		goto out_disable;