From 9bb04d3aa6a2b1b86e091967e312a19ce337df4d Mon Sep 17 00:00:00 2001
From: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date: Wed, 3 Dec 2014 16:12:49 -0200
Subject: lib: add igt_wait()

Just a little helper for code that needs to wait for a certain
condition to happen. It has the nice advantage that it can survive the
signal helper.

Despite the callers added in this patch, there is another that will go
in a separate patch, and another in a new IGT test file that I plan to
push later.

v2: Check COND again before returning in case we hit the timeout.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
 lib/igt_aux.c | 18 +-----------------
 lib/igt_aux.h | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 17 deletions(-)

(limited to 'lib')

diff --git a/lib/igt_aux.c b/lib/igt_aux.c
index e011ef4e..84b84e4a 100644
--- a/lib/igt_aux.c
+++ b/lib/igt_aux.c
@@ -606,29 +606,13 @@ enum igt_runtime_pm_status igt_get_runtime_pm_status(void)
  * Waits until for the driver to switch to into the desired runtime PM status,
  * with a 10 second timeout.
  *
- * Some subtests call this function while the signal helper is active, so we
- * can't assume each usleep() call will sleep for 100ms.
- *
  * Returns:
  * True if the desired runtime PM status was attained, false if the operation
  * timed out.
  */
 bool igt_wait_for_pm_status(enum igt_runtime_pm_status status)
 {
-	struct timeval start, end, diff;
-
-	igt_assert(gettimeofday(&start, NULL) == 0);
-	do {
-		if (igt_get_runtime_pm_status() == status)
-			return true;
-
-		usleep(100 * 1000);
-
-		igt_assert(gettimeofday(&end, NULL) == 0);
-		timersub(&end, &start, &diff);
-	} while (diff.tv_sec < 10);
-
-	return false;
+	return igt_wait(igt_get_runtime_pm_status() == status, 10000, 100);
 }
 
 /* Functions with prefix kmstest_ independent of cairo library are pulled out
diff --git a/lib/igt_aux.h b/lib/igt_aux.h
index 7a5078b0..b2dc2679 100644
--- a/lib/igt_aux.h
+++ b/lib/igt_aux.h
@@ -30,6 +30,7 @@
 
 #include <intel_bufmgr.h>
 #include <stdbool.h>
+#include <sys/time.h>
 
 extern drm_intel_bo **trash_bos;
 extern int num_trash_bos;
@@ -102,4 +103,46 @@ void intel_require_memory(uint32_t count, uint32_t size, unsigned mode);
 void igt_lock_mem(size_t size);
 void igt_unlock_mem(void);
 
+/**
+ * igt_wait:
+ * @COND: condition to wait
+ * @timeout_ms: timeout in milliseconds
+ * @interval_ms: amount of time we try to sleep between COND checks
+ *
+ * Waits until COND evaluates to true or the timeout passes.
+ *
+ * It is safe to call this macro if the signal helper is active. The only
+ * problem is that the usleep() calls will return early, making us evaluate COND
+ * too often, possibly eating valuable CPU cycles.
+ *
+ * Returns:
+ * True of COND evaluated to true, false otherwise.
+ */
+#define igt_wait(COND, timeout_ms, interval_ms) ({			\
+	struct timeval start_, end_, diff_;				\
+	int elapsed_ms_;						\
+	bool ret_ = false;						\
+									\
+	igt_assert(gettimeofday(&start_, NULL) == 0);			\
+	do {								\
+		if (COND) {						\
+			ret_ = true;					\
+			break;						\
+		}							\
+									\
+		usleep(interval_ms * 1000);				\
+									\
+		igt_assert(gettimeofday(&end_, NULL) == 0);		\
+		timersub(&end_, &start_, &diff_);			\
+									\
+		elapsed_ms_ = diff_.tv_sec * 1000 +			\
+			      diff_.tv_usec / 1000;			\
+	} while (elapsed_ms_ < timeout_ms);				\
+									\
+	if (!ret_ && (COND))						\
+		ret_ = true;						\
+									\
+	ret_;								\
+})
+
 #endif /* IGT_AUX_H */
-- 
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