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Commit c7dffff7 authored by Keith Packard's avatar Keith Packard
Browse files

drm/i915: Clean up multi-threaded forcewake patch 



We learned that the ECOBUS register was inside the GT power well, and
so *did* need force wake to be read, so it gets removed from the list
of 'doesn't need force wake' registers.

That means the code reading ECOBUS after forcing the mt_force_wake
function to be called needs to use I915_READ_NOTRACE; it doesn't need
to do more force wake fun as it's already done it manually.

This also adds a comment explaining why the MT forcewake testing code
only needs to call mt_forcewake_get/put and not disable RC6 manually
-- the ECOBUS read will return 0 if the device is in RC6 and isn't
using MT forcewake, causing the test to work correctly.

Signed-off-by: default avatarKeith Packard <keithp@keithp.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
parent 4d85529d

drivers/gpu/drm/i915/i915_drv.c

+0 −7
Original line number Original line Diff line number Diff line
@@ -923,13 +923,6 @@ MODULE_AUTHOR(DRIVER_AUTHOR); 
MODULE_DESCRIPTION(DRIVER_DESC);

MODULE_DESCRIPTION(DRIVER_DESC);

MODULE_LICENSE("GPL and additional rights");

MODULE_LICENSE("GPL and additional rights");





/* We give fast paths for the really cool registers */

#define NEEDS_FORCE_WAKE(dev_priv, reg) \

	(((dev_priv)->info->gen >= 6) && \

	 ((reg) < 0x40000) &&		 \

	 ((reg) != FORCEWAKE) &&	 \

	 ((reg) != ECOBUS))



#define __i915_read(x, y) \

#define __i915_read(x, y) \

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

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

	u##x val = 0; \

	u##x val = 0; \

drivers/gpu/drm/i915/i915_drv.h

+1 −2
Original line number Original line Diff line number Diff line
@@ -1364,8 +1364,7 @@ void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv); 
#define NEEDS_FORCE_WAKE(dev_priv, reg) \

#define NEEDS_FORCE_WAKE(dev_priv, reg) \

	(((dev_priv)->info->gen >= 6) && \

	(((dev_priv)->info->gen >= 6) && \

	 ((reg) < 0x40000) &&		 \

	 ((reg) < 0x40000) &&		 \

	 ((reg) != FORCEWAKE) &&	 \

	 ((reg) != FORCEWAKE))

	 ((reg) != ECOBUS))





#define __i915_read(x, y) \

#define __i915_read(x, y) \

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

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

drivers/gpu/drm/i915/intel_display.c

+7 −1
Original line number Original line Diff line number Diff line
@@ -8591,9 +8591,15 @@ static void intel_init_display(struct drm_device *dev) 
		if (IS_IVYBRIDGE(dev)) {

		if (IS_IVYBRIDGE(dev)) {

			u32	ecobus;

			u32	ecobus;





			/* A small trick here - if the bios hasn't configured MT forcewake,

			 * and if the device is in RC6, then force_wake_mt_get will not wake

			 * the device and the ECOBUS read will return zero. Which will be

			 * (correctly) interpreted by the test below as MT forcewake being

			 * disabled.

			 */

			mutex_lock(&dev->struct_mutex);

			mutex_lock(&dev->struct_mutex);

			__gen6_gt_force_wake_mt_get(dev_priv);

			__gen6_gt_force_wake_mt_get(dev_priv);

			ecobus = I915_READ(ECOBUS);

			ecobus = I915_READ_NOTRACE(ECOBUS);

			__gen6_gt_force_wake_mt_put(dev_priv);

			__gen6_gt_force_wake_mt_put(dev_priv);

			mutex_unlock(&dev->struct_mutex);

			mutex_unlock(&dev->struct_mutex);