Usually the condition we are after appears within very short time.
Spin few times before going into sleep. With this approximately
half of the wait_for in init path will take the fast path without
sleeping.
Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_drv.h | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 488141929a7a..c225605c727c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -39,7 +39,7 @@
#include <drm/drm_atomic.h>
/**
- * _wait_for_ms - magic (register) wait macro
+ * __wait_for_ms - magic (register) wait macro
*
* Does the right thing for modeset paths when run under kdgb or similar atomic
* contexts. Note that it's important that we check the condition again after
@@ -50,17 +50,22 @@
* drm_can_sleep() can be removed and in_atomic()/!in_atomic() asserts
* added.
*/
-#define _wait_for_ms(COND, TIMEOUT_MS, SLEEP_US) ({ \
+#define __wait_for_ms(COND, TIMEOUT_MS, SLEEP_US, SPIN_COUNT) ({ \
const unsigned long timeout__ = \
jiffies + msecs_to_jiffies(TIMEOUT_MS) + 1; \
+ unsigned int c__ = 0; \
int ret__ = 0; \
+ \
while (!(COND)) { \
if (time_after(jiffies, timeout__)) { \
if (!(COND)) \
ret__ = -ETIMEDOUT; \
break; \
} \
- if ((SLEEP_US) && drm_can_sleep()) { \
+ \
+ if (++c__ > (SPIN_COUNT) && \
+ (SLEEP_US) && \
+ drm_can_sleep()) { \
usleep_range((SLEEP_US), (SLEEP_US) * 2); \
} else { \
cpu_relax(); \
@@ -69,7 +74,8 @@
ret__; \
})
-#define wait_for(COND, MS) _wait_for_ms((COND), (MS), 1 * USEC_PER_MSEC)
+#define wait_for(COND, MS) __wait_for_ms((COND), (MS), 1 * USEC_PER_MSEC, 5)
+#define _wait_for_ms(COND, MS, US) __wait_for_ms((COND), (MS), (US), 5)
/* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */
#if defined(CONFIG_DRM_I915_DEBUG) && defined(CONFIG_PREEMPT_COUNT)
--
2.5.0
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