[Intel-gfx] [PATCH] drm/i915: Do not lie about atomic wait granularity
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Mon Feb 1 13:17:35 UTC 2016
From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Currently the wait_for_atomic_us only allows for a millisecond
granularity which is not nice towards callers requesting small
micro-second waits.
Re-implement it so micro-second granularity is really supported
and not just in the name of the macro.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
Danger - this might break things which currently work by accident!
---
drivers/gpu/drm/i915/intel_drv.h | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index f620023ed134..9e8a1202194c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -63,10 +63,25 @@
ret__; \
})
+#define _wait_for_atomic(COND, US) ({ \
+ unsigned long end__; \
+ int ret__ = 0; \
+ get_cpu(); \
+ end__ = (local_clock() >> 10) + (US) + 1; \
+ while (!(COND)) { \
+ if (time_after((unsigned long)(local_clock() >> 10), end__)) { \
+ ret__ = -ETIMEDOUT; \
+ break; \
+ } \
+ cpu_relax(); \
+ } \
+ put_cpu(); \
+ ret__; \
+})
+
#define wait_for(COND, MS) _wait_for(COND, MS, 1)
-#define wait_for_atomic(COND, MS) _wait_for(COND, MS, 0)
-#define wait_for_atomic_us(COND, US) _wait_for((COND), \
- DIV_ROUND_UP((US), 1000), 0)
+#define wait_for_atomic(COND, MS) _wait_for_atomic(COND, (MS * 1000))
+#define wait_for_atomic_us(COND, US) _wait_for_atomic((COND), (US))
#define KHz(x) (1000 * (x))
#define MHz(x) KHz(1000 * (x))
--
1.9.1
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