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Commit a8b1397d authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/i915: implement WaIssueDummyWriteToWakeupFromRC6 



Or at least our best understanding of it.

v2: Fixup commit message and put the wa name into the comment block.
And actually update the commit, too.

Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 5a35e99e

drivers/gpu/drm/i915/i915_drv.c

+13 −0
Original line number Diff line number Diff line
@@ -1131,9 +1131,20 @@ static bool IS_DISPLAYREG(u32 reg) 
	return true;

}



static void

ilk_dummy_write(struct drm_i915_private *dev_priv)

{

	/* WaIssueDummyWriteToWakeupFromRC6: Issue a dummy write to wake up the

	 * chip from rc6 before touching it for real. MI_MODE is masked, hence

	 * harmless to write 0 into. */

	I915_WRITE_NOTRACE(MI_MODE, 0);

}



#define __i915_read(x, y) \

u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \

	u##x val = 0; \

	if (IS_GEN5(dev_priv->dev)) \

		ilk_dummy_write(dev_priv); \

	if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \

		unsigned long irqflags; \

		spin_lock_irqsave(&dev_priv->gt_lock, irqflags); \
@@ -1165,6 +1176,8 @@ void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \ 
	if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \

		__fifo_ret = __gen6_gt_wait_for_fifo(dev_priv); \

	} \

	if (IS_GEN5(dev_priv->dev)) \

		ilk_dummy_write(dev_priv); \

	if (IS_VALLEYVIEW(dev_priv->dev) && IS_DISPLAYREG(reg)) { \

		write##y(val, dev_priv->regs + reg + 0x180000);		\

	} else {							\