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Commit 9517a92f authored by Jesse Barnes's avatar Jesse Barnes Committed by Eric Anholt
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drm/i915: add timeout to FBC disable waits 

FBC disable on 965 can take long enough to trigger latency checks in the
kernel so be sure to timeout after a reasonable period.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=15015

.

Tested-by: default avatarJames Ettle <theholyettlz@googlemail.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarEric Anholt <eric@anholt.net>
parent d1b851fc

drivers/gpu/drm/i915/intel_display.c

+11 −2
Original line number Diff line number Diff line
@@ -1029,19 +1029,28 @@ static void i8xx_enable_fbc(struct drm_crtc *crtc, unsigned long interval) 
void i8xx_disable_fbc(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	unsigned long timeout = jiffies + msecs_to_jiffies(1);

	u32 fbc_ctl;



	if (!I915_HAS_FBC(dev))

		return;



	if (!(I915_READ(FBC_CONTROL) & FBC_CTL_EN))

		return;	/* Already off, just return */



	/* Disable compression */

	fbc_ctl = I915_READ(FBC_CONTROL);

	fbc_ctl &= ~FBC_CTL_EN;

	I915_WRITE(FBC_CONTROL, fbc_ctl);



	/* Wait for compressing bit to clear */

	while (I915_READ(FBC_STATUS) & FBC_STAT_COMPRESSING)

		; /* nothing */

	while (I915_READ(FBC_STATUS) & FBC_STAT_COMPRESSING) {

		if (time_after(jiffies, timeout)) {

			DRM_DEBUG_DRIVER("FBC idle timed out\n");

			break;

		}

		; /* do nothing */

	}



	intel_wait_for_vblank(dev);