[PATCH v3 1/2] tests/intel/sysfs: Restore sysfs values on test failure

[Jonathan Cavitt <jonathan.cavitt@intel.com>]

The tests xe_sysfs_preempt_timeout and xe_sysfs_timeslice_duration
modify the values of preempt_timeout_us and timeslice_duration_us,
respectively.  However, on a test failure, it is possible that these
values may remain in their modified states, resulting in the values
being used in future tests and causing unexpected behavior.

Save the respective modified values before starting the test and attempt
to restore the values on test exit.

v2:
- Fix some formatting issues (Kamil)
- Abort if value restore fails (Kamil)
- Directly call igt_sysfs_printf on exit to avoid duplicating on helper
  (Kamil)

Suggested-by: Kamil Konieczny <kamil.konieczny@linux.intel.com>
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
CC: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
---
 tests/intel/xe_sysfs_preempt_timeout.c    | 43 +++++++++++++++++------
 tests/intel/xe_sysfs_timeslice_duration.c | 42 +++++++++++++++++-----
 2 files changed, 66 insertions(+), 19 deletions(-)

diff --git a/tests/intel/xe_sysfs_preempt_timeout.c b/tests/intel/xe_sysfs_preempt_timeout.c
index 7fa0dfcdf7..3bfda826d4 100644
--- a/tests/intel/xe_sysfs_preempt_timeout.c
+++ b/tests/intel/xe_sysfs_preempt_timeout.c
@@ -170,6 +170,7 @@ static void test_timeout(int fd, int engine, const char **property, uint16_t cla
 	set_preempt_timeout(engine, saved);
 }
 
+#define	MAX_GTS	8
 igt_main
 {
 	static const struct {
@@ -183,8 +184,10 @@ igt_main
 				       "preempt_timeout_min",
 				       "preempt_timeout_max"}, };
 	int count = sizeof(property) / sizeof(property[0]);
+	int gt_count = 0;
 	int fd = -1, sys_fd, gt;
-	int engines_fd = -1, gt_fd = -1;
+	int engines_fd[MAX_GTS], gt_fd[MAX_GTS];
+	unsigned int pts[MAX_GTS];
 
 	igt_fixture {
 		fd = drm_open_driver(DRIVER_XE);
@@ -192,26 +195,46 @@ igt_main
 		sys_fd = igt_sysfs_open(fd);
 		igt_require(sys_fd != -1);
 		close(sys_fd);
+
+		xe_for_each_gt(fd, gt) {
+			igt_require(gt_count < MAX_GTS);
+
+			gt_fd[gt_count] = xe_sysfs_gt_open(fd, gt);
+			igt_require(gt_fd[gt_count] != -1);
+			engines_fd[gt_count] = openat(gt_fd[gt_count], "engines", O_RDONLY);
+			igt_require(engines_fd[gt_count] != -1);
+			igt_require(igt_sysfs_scanf(engines_fd[gt_count],
+						    "preempt_timeout_us",
+						    "%u", &pts[gt_count]) == 1);
+			gt_count++;
+		}
 	}
 
 	for (int i = 0; i < count; i++) {
 		for (typeof(*tests) *t = tests; t->name; t++) {
 			igt_subtest_with_dynamic_f("%s-%s", property[i][0], t->name) {
+				int j = 0;
 				xe_for_each_gt(fd, gt) {
-					gt_fd = xe_sysfs_gt_open(fd, gt);
-					igt_require(gt_fd != -1);
-					engines_fd = openat(gt_fd, "engines", O_RDONLY);
-					igt_require(engines_fd != -1);
-
-					igt_sysfs_engines(fd, engines_fd, gt, 1, property[i],
-									  t->fn);
-					close(engines_fd);
-					close(gt_fd);
+					int e = engines_fd[j];
+					igt_sysfs_engines(fd, e, gt, 1, property[i], t->fn);
+					j++;
 				}
 			}
 		}
 	}
 	igt_fixture {
+		for (int i = gt_count - 1; i >= 0; i--) {
+			int store;
+
+			igt_assert_lte(0, igt_sysfs_printf(engines_fd[i], "preempt_timeout_us",
+							   "%u", pts[i]));
+			igt_sysfs_scanf(engines_fd[i], "preempt_timeout_us", "%u", &store);
+			igt_abort_on_f(store != pts[i], "preempt_timeout_us not restored!\n");
+
+			close(engines_fd[i]);
+			close(gt_fd[i]);
+		}
+
 		drm_close_driver(fd);
 	}
 }
diff --git a/tests/intel/xe_sysfs_timeslice_duration.c b/tests/intel/xe_sysfs_timeslice_duration.c
index cf95a3ac1c..b34d78a784 100644
--- a/tests/intel/xe_sysfs_timeslice_duration.c
+++ b/tests/intel/xe_sysfs_timeslice_duration.c
@@ -142,6 +142,7 @@ static void test_timeout(int fd, int engine, const char **property, uint16_t cla
 	set_timeslice_duration(engine, saved);
 }
 
+#define	MAX_GTS	8
 igt_main
 {
 	static const struct {
@@ -155,8 +156,10 @@ igt_main
 				       "timeslice_duration_min",
 				       "timeslice_duration_max"}, };
 	int count = sizeof(property) / sizeof(property[0]);
+	int gt_count = 0;
 	int fd = -1, sys_fd, gt;
-	int engines_fd = -1, gt_fd = -1;
+	int engines_fd[MAX_GTS], gt_fd[MAX_GTS];
+	unsigned int tds[MAX_GTS];
 
 	igt_fixture {
 		fd = drm_open_driver(DRIVER_XE);
@@ -164,25 +167,46 @@ igt_main
 		sys_fd = igt_sysfs_open(fd);
 		igt_require(sys_fd != -1);
 		close(sys_fd);
+
+		xe_for_each_gt(fd, gt) {
+			igt_require(gt_count < MAX_GTS);
+
+			gt_fd[gt_count] = xe_sysfs_gt_open(fd, gt);
+			igt_require(gt_fd[gt_count] != -1);
+			engines_fd[gt_count] = openat(gt_fd[gt_count], "engines", O_RDONLY);
+			igt_require(engines_fd[gt_count] != -1);
+			igt_require(igt_sysfs_scanf(engines_fd[gt_count],
+						    "timeslice_duration_us",
+						    "%u", &tds[gt_count]) == 1);
+			gt_count++;
+		}
 	}
 
 	for (int i = 0; i < count; i++) {
 		for (typeof(*tests) *t = tests; t->name; t++) {
 			igt_subtest_with_dynamic_f("%s-%s", property[i][0], t->name) {
+				int j = 0;
 				xe_for_each_gt(fd, gt) {
-					gt_fd = xe_sysfs_gt_open(fd, gt);
-					igt_require(gt_fd != -1);
-					engines_fd = openat(gt_fd, "engines", O_RDONLY);
-					igt_require(engines_fd != -1);
-					igt_sysfs_engines(fd, engines_fd, gt, 1, property[i],
-										 t->fn);
-					close(engines_fd);
-					close(gt_fd);
+					int e = engines_fd[j];
+					igt_sysfs_engines(fd, e, gt, 1, property[i], t->fn);
+					j++;
 				}
 			}
 		}
 	}
 	igt_fixture {
+		for (int i = gt_count - 1; i >= 0; i--) {
+			unsigned int store;
+
+			igt_assert_lte(0, igt_sysfs_printf(engines_fd[i], "timeslice_duration_us",
+							   "%u", tds[i]));
+			igt_sysfs_scanf(engines_fd[i], "timeslice_duration_us", "%u", &store);
+			igt_abort_on_f(store != tds[i], "timeslice_duration_us not restored!\n");
+
+			close(engines_fd[i]);
+			close(gt_fd[i]);
+		}
+
 		drm_close_driver(fd);
 	}
 }
-- 
2.43.0