[Intel-gfx] [PATCH i-g-t] lib/pm: Fix some runtime PM issues

[Tvrtko Ursulin <tursulin@ursulin.net>]

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

1.

It seems that on many systems the hardcoded PCI path in
igt_pm_audio_setup_runtime_pm is not correct.

Add some more paths to work around the issue. More robust solution would
be to look for a symlink of a specific format and use that, such as:

 # ls -ld /sys/bus/pci/drivers/snd_hda_intel/0000\:00\:1f.3/
 drwxr-xr-x 7 root root 0 Jul 20 14:48 /sys/bus/pci/drivers/snd_hda_intel/0000:00:1f.3/

But that's more work, so leave it for a rainy day.

2.

Cleanup handlers were not signal safe - rewrite them.

3.

Along the way I can also export the explicit cleanup function to be called
from individual test cases where that is wanted.

4.

Call the cleanup explicitly from perf_pmu/rc6-runtime-pm.

v2:
 * Skip double restore. (Chris Wilson)
 * Close previously leaked fd.

v3:
 * Refactor atexit handlers to be signal safe. (Chris Wilson)
 * Restore audio runtime PM status.
 * Add a different PCI path to audio device.

v4:
 * Patch renamed and commit message improved.
 * Add another possible PCI bus location.

v5:
 * Wrong PCI device.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> # v3
---
Dear Santa,

Please don't make this split this up - at least not today since it is
Friday and an unusually warm day! :)
---
 lib/igt_pm.c     | 153 ++++++++++++++++++++++++++++++++++++-----------
 lib/igt_pm.h     |   1 +
 tests/perf_pmu.c |   3 +
 3 files changed, 123 insertions(+), 34 deletions(-)

diff --git a/lib/igt_pm.c b/lib/igt_pm.c
index 8ac132269d79..df7b2cd16d66 100644
--- a/lib/igt_pm.c
+++ b/lib/igt_pm.c
@@ -63,36 +63,74 @@ enum {
 /* Remember to fix this if adding longer strings */
 #define MAX_POLICY_STRLEN	strlen(MAX_PERFORMANCE_STR)
 
+static const char *const __igt_pm_audio_runtime_control_paths[] = {
+	"/sys/bus/pci/devices/0000:00:03.0/power/control",
+	"/sys/bus/pci/devices/0000:00:0e.0/power/control",
+	"/sys/bus/pci/devices/0000:00:1f.3/power/control",
+};
+
 static char __igt_pm_audio_runtime_power_save[64];
+static const char * __igt_pm_audio_runtime_control_path;
 static char __igt_pm_audio_runtime_control[64];
 
-static void __igt_pm_audio_runtime_exit_handler(int sig)
+static int __igt_pm_audio_restore_runtime_pm(void)
 {
 	int fd;
 
-	igt_debug("Restoring audio power management to '%s' and '%s'\n",
-		  __igt_pm_audio_runtime_power_save,
-		  __igt_pm_audio_runtime_control);
+	if (!__igt_pm_audio_runtime_power_save[0])
+		return 0;
 
 	fd = open("/sys/module/snd_hda_intel/parameters/power_save", O_WRONLY);
 	if (fd < 0)
-		return;
+		return errno;
+
 	if (write(fd, __igt_pm_audio_runtime_power_save,
 		  strlen(__igt_pm_audio_runtime_power_save)) !=
-	    strlen(__igt_pm_audio_runtime_power_save))
-		igt_warn("Failed to restore audio power_save to '%s'\n",
-			 __igt_pm_audio_runtime_power_save);
+	    strlen(__igt_pm_audio_runtime_power_save)) {
+		close(fd);
+		return errno;
+	}
+
 	close(fd);
 
-	fd = open("/sys/bus/pci/devices/0000:00:03.0/power/control", O_WRONLY);
+	fd = open(__igt_pm_audio_runtime_control_path, O_WRONLY);
 	if (fd < 0)
-		return;
+		return errno;
+
 	if (write(fd, __igt_pm_audio_runtime_control,
 		  strlen(__igt_pm_audio_runtime_control)) !=
-	    strlen(__igt_pm_audio_runtime_control))
-		igt_warn("Failed to restore audio control to '%s'\n",
-			 __igt_pm_audio_runtime_control);
+	    strlen(__igt_pm_audio_runtime_control)) {
+		close(fd);
+		return errno;
+	}
+
 	close(fd);
+
+	__igt_pm_audio_runtime_power_save[0] = 0;
+
+	return 0;
+}
+
+static void igt_pm_audio_restore_runtime_pm(void)
+{
+	int ret;
+
+	if (!__igt_pm_audio_runtime_power_save[0])
+		return;
+
+	igt_debug("Restoring audio power management to '%s' and '%s'\n",
+		  __igt_pm_audio_runtime_power_save,
+		  __igt_pm_audio_runtime_control);
+
+	ret = __igt_pm_audio_restore_runtime_pm();
+	if (ret)
+		igt_warn("Failed to restore runtime audio PM! (errno=%d)\n",
+			 ret);
+}
+
+static void __igt_pm_audio_runtime_exit_handler(int sig)
+{
+	__igt_pm_audio_restore_runtime_pm();
 }
 
 static void strchomp(char *str)
@@ -116,7 +154,7 @@ static void strchomp(char *str)
  */
 void igt_pm_enable_audio_runtime_pm(void)
 {
-	int fd;
+	int fd, i;
 
 	/* Check if already enabled. */
 	if (__igt_pm_audio_runtime_power_save[0])
@@ -131,14 +169,23 @@ void igt_pm_enable_audio_runtime_pm(void)
 		igt_assert_eq(write(fd, "1\n", 2), 2);
 		close(fd);
 	}
-	fd = open("/sys/bus/pci/devices/0000:00:03.0/power/control", O_RDWR);
-	if (fd >= 0) {
-		igt_assert(read(fd, __igt_pm_audio_runtime_control,
-				sizeof(__igt_pm_audio_runtime_control)) > 0);
-		strchomp(__igt_pm_audio_runtime_control);
-		igt_assert_eq(write(fd, "auto\n", 5), 5);
-		close(fd);
+
+	for (i = 0; i < ARRAY_SIZE(__igt_pm_audio_runtime_control_paths); i++) {
+		const char *path = __igt_pm_audio_runtime_control_paths[i];
+
+		fd = open(path, O_RDWR);
+		if (fd >= 0) {
+			__igt_pm_audio_runtime_control_path = path;
+			igt_assert(read(fd, __igt_pm_audio_runtime_control,
+					sizeof(__igt_pm_audio_runtime_control)) > 0);
+			strchomp(__igt_pm_audio_runtime_control);
+			igt_assert_eq(write(fd, "auto\n", 5), 5);
+			close(fd);
+			break;
+		}
 	}
+	if (!__igt_pm_audio_runtime_control_path)
+		igt_warn("Failed to find audio PCI device!\n");
 
 	igt_debug("Saved audio power management as '%s' and '%s'\n",
 		  __igt_pm_audio_runtime_power_save,
@@ -291,39 +338,77 @@ void igt_pm_restore_sata_link_power_management(int8_t *pm_data)
 	free(file_name);
 }
 #define POWER_DIR "/sys/devices/pci0000:00/0000:00:02.0/power"
-/* We just leak this on exit ... */
 int pm_status_fd = -1;
 
 static char __igt_pm_runtime_autosuspend[64];
 static char __igt_pm_runtime_control[64];
 
-static void __igt_pm_runtime_exit_handler(int sig)
+static int __igt_restore_runtime_pm(void)
 {
 	int fd;
 
-	igt_debug("Restoring runtime management to '%s' and '%s'\n",
-		  __igt_pm_runtime_autosuspend,
-		  __igt_pm_runtime_control);
+	if (pm_status_fd < 0)
+		return 0;
 
 	fd = open(POWER_DIR "/autosuspend_delay_ms", O_WRONLY);
 	if (fd < 0)
-		return;
+		return errno;
+
 	if (write(fd, __igt_pm_runtime_autosuspend,
 		  strlen(__igt_pm_runtime_autosuspend)) !=
-	    strlen(__igt_pm_runtime_autosuspend))
-		igt_warn("Failed to restore runtime pm autosuspend delay to '%s'\n",
-			 __igt_pm_runtime_autosuspend);
+	    strlen(__igt_pm_runtime_autosuspend)) {
+		close(fd);
+		return errno;
+	}
+
 	close(fd);
 
 	fd = open(POWER_DIR "/control", O_WRONLY);
 	if (fd < 0)
-		return;
+		return errno;
+
 	if (write(fd, __igt_pm_runtime_control,
 		  strlen(__igt_pm_runtime_control)) !=
-	    strlen(__igt_pm_runtime_control))
-		igt_warn("Failed to restore runtime pm control to '%s'\n",
-			 __igt_pm_runtime_control);
+	    strlen(__igt_pm_runtime_control)) {
+		close(fd);
+		return errno;
+	}
+
 	close(fd);
+
+	close(pm_status_fd);
+	pm_status_fd = -1;
+
+	return 0;
+}
+
+/**
+ * igt_restore_runtime_pm:
+ *
+ * Restores the runtime PM configuration as it was before the call to
+ * igt_setup_runtime_pm.
+ */
+void igt_restore_runtime_pm(void)
+{
+	int ret;
+
+	if (pm_status_fd < 0)
+		return;
+
+	igt_debug("Restoring runtime PM management to '%s' and '%s'\n",
+		  __igt_pm_runtime_autosuspend,
+		  __igt_pm_runtime_control);
+
+	ret = __igt_restore_runtime_pm();
+	if (ret)
+		igt_warn("Failed to restore runtime PM! (errno=%d)\n", ret);
+
+	igt_pm_audio_restore_runtime_pm();
+}
+
+static void __igt_pm_runtime_exit_handler(int sig)
+{
+	__igt_restore_runtime_pm();
 }
 
 /**
diff --git a/lib/igt_pm.h b/lib/igt_pm.h
index eced39f8801a..10cc6794e4e7 100644
--- a/lib/igt_pm.h
+++ b/lib/igt_pm.h
@@ -47,6 +47,7 @@ enum igt_runtime_pm_status {
 };
 
 bool igt_setup_runtime_pm(void);
+void igt_restore_runtime_pm(void);
 enum igt_runtime_pm_status igt_get_runtime_pm_status(void);
 bool igt_wait_for_pm_status(enum igt_runtime_pm_status status);
 
diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c
index a1d36ac4fa9d..9a20abb6b95c 100644
--- a/tests/perf_pmu.c
+++ b/tests/perf_pmu.c
@@ -1441,6 +1441,9 @@ test_rc6(int gem_fd, unsigned int flags)
 	close(fw);
 	close(fd);
 
+	if (flags & TEST_RUNTIME_PM)
+		igt_restore_runtime_pm();
+
 	assert_within_epsilon(busy - prev, 0.0, tolerance);
 }
 
-- 
2.17.1

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