3.2.95-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Keith Packard <[email protected]> commit c7dffff7cc8de748edf0e9f6571cdabecb198705 upstream. 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 <[email protected]> Cc: Jesse Barnes <[email protected]> [bwh: Backported to 3.2: I previously backported a change to NEEDS_FORCE_WAKE() and applied it to the version in i915_drv.c, the one that was actually being used. Move that change to i915_drv.h now.] Signed-off-by: Ben Hutchings <[email protected]> --- drivers/gpu/drm/i915/i915_drv.c | 7 ------- drivers/gpu/drm/i915/i915_drv.h | 3 +-- drivers/gpu/drm/i915/intel_display.c | 8 +++++++- 3 files changed, 8 insertions(+), 10 deletions(-) --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -971,13 +971,6 @@ 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) \ - ((HAS_FORCE_WAKE((dev_priv)->dev)) && \ - ((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; \ --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1369,10 +1369,9 @@ void __gen6_gt_wait_for_fifo(struct drm_ /* We give fast paths for the really cool registers */ #define NEEDS_FORCE_WAKE(dev_priv, reg) \ - (((dev_priv)->info->gen >= 6) && \ + ((HAS_FORCE_WAKE((dev_priv)->dev)) && \ ((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); --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8699,9 +8699,15 @@ static void intel_init_display(struct dr 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);
