diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2012-06-13 18:29:52 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2012-06-19 21:16:02 +0200 |
| commit | 7d3e982b10de522d5a881b9df569357f83ffd7aa (patch) | |
| tree | 76adeb2b4f3ad713440d5c6652dfdea0494c2728 | |
| parent | 400d7414c11c05141c1cb4016cbc60c8299280d3 (diff) | |
drm/i915: Implement w/a for sporadic read failures on waking from rc6for-jirierab
As a w/a to prevent reads sporadically returning 0, we need to wait for
the GT thread to return to TC0 before proceeding to read the registers.
References: https://bugs.freedesktop.org/show_bug.cgi?id=50243
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.c | 19 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_reg.h | 3 |
2 files changed, 22 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 440c8f2250b3..e5b7a2fcd772 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -430,6 +430,19 @@ bool i915_semaphore_is_enabled(struct drm_device *dev) return 1; } +static void __gen6_gt_wait_for_thread_c0(struct drm_i915_private *dev_priv) +{ + unsigned long timeout; + + /* w/a for a sporadic read returning 0 by waiting for the GT + * thread to wake up. + */ + timeout = jiffies + msecs_to_jiffies(1); + while (I915_READ_NOTRACE(GEN6_GT_THREAD_STATUS_REG) & GEN6_GT_THREAD_STATUS_CORE_MASK && + time_before(jiffies, timeout)) + ; +} + static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv) { unsigned long timeout; @@ -445,6 +458,8 @@ static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv) while ((I915_READ_NOTRACE(FORCEWAKE_ACK) & 1) == 0 && time_before(jiffies, timeout)) ; + + __gen6_gt_wait_for_thread_c0(dev_priv); } static void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv) @@ -462,6 +477,8 @@ static void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv) while ((I915_READ_NOTRACE(FORCEWAKE_MT_ACK) & 1) == 0 && time_before(jiffies, timeout)) ; + + __gen6_gt_wait_for_thread_c0(dev_priv); } /* @@ -552,6 +569,8 @@ static void vlv_force_wake_get(struct drm_i915_private *dev_priv) count = 0; while (count++ < 50 && (I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & 1) == 0) udelay(10); + + __gen6_gt_wait_for_thread_c0(dev_priv); } static void vlv_force_wake_put(struct drm_i915_private *dev_priv) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 48d5e8e051cf..bc28d6baf5ee 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -1453,6 +1453,9 @@ #define DDRMPLL1 0X12c20 #define PEG_BAND_GAP_DATA 0x14d68 +#define GEN6_GT_THREAD_STATUS_REG 0x13805c +#define GEN6_GT_THREAD_STATUS_CORE_MASK 0x7 + #define GEN6_GT_PERF_STATUS 0x145948 #define GEN6_RP_STATE_LIMITS 0x145994 #define GEN6_RP_STATE_CAP 0x145998 |