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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: Keith Packard <keithp@keithp.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Keith Packard 2011-12-09 11:33:00 -08:00
parent 4d85529d58
commit c7dffff7cc
3 changed files with 8 additions and 10 deletions
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7
drivers/gpu/drm/i915/i915_drv.c
View File

@ -923,13 +923,6 @@ MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
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) \
u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
u##x val = 0; \

3
drivers/gpu/drm/i915/i915_drv.h
View File

@ -1364,8 +1364,7 @@ void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv);
#define NEEDS_FORCE_WAKE(dev_priv, reg) \
(((dev_priv)->info->gen >= 6) && \
((reg) < 0x40000) && \
((reg) != FORCEWAKE) && \
((reg) != ECOBUS))
((reg) != FORCEWAKE))
#define __i915_read(x, y) \
u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg);

8
drivers/gpu/drm/i915/intel_display.c
View File

@ -8591,9 +8591,15 @@ static void intel_init_display(struct drm_device *dev)
if (IS_IVYBRIDGE(dev)) {
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);
__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);
mutex_unlock(&dev->struct_mutex);