From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
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.
v2:
* Warn when used from non-atomic context (if possible).
* Warn on too long atomic waits.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_drv.h | 27 ++++++++++++++++++++++++---
1 file changed, 24 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 779d17a9fcce..af6c1539106f 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -63,11 +63,32 @@
ret__; \
})
+#if defined(CONFIG_DRM_I915_DEBUG) && defined(CONFIG_PREEMPT_COUNT)
+ #define _WAIT_FOR_ATOMIC_CHECK WARN_ON_ONCE(!in_atomic())
+#else
+ #define _WAIT_FOR_ATOMIC_CHECK do { } while(0)
+#endif
+
+#define _wait_for_atomic(COND, US) ({ \
+ unsigned long end__; \
+ int ret__ = 0; \
+ _WAIT_FOR_ATOMIC_CHECK; \
+ BUILD_BUG_ON((US) > 50000); \
+ end__ = (local_clock() >> 10) + (US) + 1; \
+ while (!(COND)) { \
+ if (time_after((unsigned long)(local_clock() >> 10), end__)) { \
+ ret__ = -ETIMEDOUT; \
+ break; \
+ } \
+ cpu_relax(); \
+ } \
+ ret__; \
+})
+
#define wait_for(COND, MS) _wait_for(COND, (MS) * 1000, 1000)
#define wait_for_us(COND, US) _wait_for(COND, US, 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
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
