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Commit b5aa8a0f authored by Grégoire Henry's avatar Grégoire Henry Committed by Eric Anholt
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drm/i915: initialize fence registers to zero when loading GEM 



Unitialized fence register could leads to corrupted display. Problem
encountered on MacBooks (revision 1 and 2), directly booting from EFI
or through BIOS emulation.

(bug #21710 at freedestop.org)

Signed-off-by: default avatarGrégoire Henry <henry@pps.jussieu.fr>
Signed-off-by: default avatarEric Anholt <eric@anholt.net>
parent 56d21b07

drivers/gpu/drm/i915/i915_gem.c

+13 −0
Original line number Diff line number Diff line
@@ -4227,6 +4227,7 @@ i915_gem_lastclose(struct drm_device *dev) 
void

i915_gem_load(struct drm_device *dev)

{

	int i;

	drm_i915_private_t *dev_priv = dev->dev_private;



	spin_lock_init(&dev_priv->mm.active_list_lock);
@@ -4246,6 +4247,18 @@ i915_gem_load(struct drm_device *dev) 
	else

		dev_priv->num_fence_regs = 8;



	/* Initialize fence registers to zero */

	if (IS_I965G(dev)) {

		for (i = 0; i < 16; i++)

			I915_WRITE64(FENCE_REG_965_0 + (i * 8), 0);

	} else {

		for (i = 0; i < 8; i++)

			I915_WRITE(FENCE_REG_830_0 + (i * 4), 0);

		if (IS_I945G(dev) || IS_I945GM(dev) || IS_G33(dev))

			for (i = 0; i < 8; i++)

				I915_WRITE(FENCE_REG_945_8 + (i * 4), 0);

	}



	i915_gem_detect_bit_6_swizzle(dev);

}