[Intel-gfx] [PATCH] lib/igt_aux: make igt_wait_for_pm_status() resist the signal helper

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni at intel.com>

If the signal helper is active, the usleep() calls return earlier, and
we may end up returning false way before the 10s timeout, failing the
subtests. This currently happens on the kms_flip RPM interruptible
subtests.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78893
Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 lib/igt_aux.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/lib/igt_aux.c b/lib/igt_aux.c
index b32297e..01654f0 100644
--- a/lib/igt_aux.c
+++ b/lib/igt_aux.c
@@ -42,6 +42,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/wait.h>
+#include <sys/time.h>
 #include <sys/types.h>
 #include <sys/syscall.h>
 #include <sys/utsname.h>
@@ -502,21 +503,27 @@ 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)
 {
-	int i;
-	int hundred_ms = 100 * 1000, ten_s = 10 * 1000 * 1000;
+	struct timeval start, end, diff;
 
-	for (i = 0; i < ten_s; i += hundred_ms) {
+	igt_assert(gettimeofday(&start, NULL) == 0);
+	do {
 		if (igt_get_runtime_pm_status() == status)
 			return true;
 
-		usleep(hundred_ms);
-	}
+		usleep(100 * 1000);
+
+		igt_assert(gettimeofday(&end, NULL) == 0);
+		timersub(&end, &start, &diff);
+	} while (diff.tv_sec < 10);
 
 	return false;
 }
-- 
1.9.1