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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2011-05-12 22:17:09 +0100 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2011-07-13 11:28:07 -0700 |
| commit | 95736720fc866eadb2ce1789631b907c0f38cb7c (patch) | |
| tree | 5071fe60b3cdd5951e351e1565121287aa17675a /drivers | |
| parent | f5a3d0c4086d1854cbda545092c462b84cba20ce (diff) | |
| download | linux-95736720fc866eadb2ce1789631b907c0f38cb7c.tar.gz linux-95736720fc866eadb2ce1789631b907c0f38cb7c.tar.bz2 linux-95736720fc866eadb2ce1789631b907c0f38cb7c.zip | |
drm/i915: Cache GT fifo count for SandyBridge
The read back of the available FIFO entries is vital for system
stability, but extremely costly. However, we only need a guide so as to
avoid eating into the reserved entries and since we are the only
consumer we can cache the read of the count from the last write.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.c | 15 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.h | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_reg.h | 1 |
3 files changed, 12 insertions, 5 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 6ed73ae2133a..d988cc350f66 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -348,12 +348,17 @@ void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv) void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv) { - int loop = 500; - u32 fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); - while (fifo < 20 && loop--) { - udelay(10); - fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + if (dev_priv->gt_fifo_count < GT_FIFO_NUM_RESERVED_ENTRIES ) { + int loop = 500; + u32 fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + while (fifo <= GT_FIFO_NUM_RESERVED_ENTRIES && loop--) { + udelay(10); + fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES); + } + WARN_ON(loop < 0 && fifo <= GT_FIFO_NUM_RESERVED_ENTRIES); + dev_priv->gt_fifo_count = fifo; } + dev_priv->gt_fifo_count--; } static int i915_drm_freeze(struct drm_device *dev) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 00dc59a51ccd..b37146c4526f 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -277,6 +277,7 @@ typedef struct drm_i915_private { int relative_constants_mode; void __iomem *regs; + u32 gt_fifo_count; struct intel_gmbus { struct i2c_adapter adapter; diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 96fb0fa47c40..02db299f621a 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -3361,6 +3361,7 @@ #define FORCEWAKE_ACK 0x130090 #define GT_FIFO_FREE_ENTRIES 0x120008 +#define GT_FIFO_NUM_RESERVED_ENTRIES 20 #define GEN6_RPNSWREQ 0xA008 #define GEN6_TURBO_DISABLE (1<<31) |