[PATCH v2 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.

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    | 34 ++++++++++++++++-------
 tests/intel/xe_sysfs_timeslice_duration.c | 33 ++++++++++++++++------
 2 files changed, 48 insertions(+), 19 deletions(-)

diff --git a/tests/intel/xe_sysfs_preempt_timeout.c b/tests/intel/xe_sysfs_preempt_timeout.c
index 7fa0dfcdf7..1b9c26bfdc 100644
--- a/tests/intel/xe_sysfs_preempt_timeout.c
+++ b/tests/intel/xe_sysfs_preempt_timeout.c
@@ -183,8 +183,10 @@ 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[8], gt_fd[8];
+	unsigned int pts[8];
 
 	igt_fixture {
 		fd = drm_open_driver(DRIVER_XE);
@@ -192,26 +194,38 @@ igt_main
 		sys_fd = igt_sysfs_open(fd);
 		igt_require(sys_fd != -1);
 		close(sys_fd);
+
+		xe_for_each_gt(fd, gt) {
+			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_assert(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);
+					igt_sysfs_engines(fd, engines_fd[j], gt, 1, property[i],
+										    t->fn);
+					j++;
 				}
 			}
 		}
 	}
 	igt_fixture {
+		for (int i = gt_count - 1; i >= 0; i--) {
+			set_preempt_timeout(engines_fd[i], pts[i]);
+			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..914575a282 100644
--- a/tests/intel/xe_sysfs_timeslice_duration.c
+++ b/tests/intel/xe_sysfs_timeslice_duration.c
@@ -155,8 +155,10 @@ 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[8], gt_fd[8];
+	unsigned int tds[8];
 
 	igt_fixture {
 		fd = drm_open_driver(DRIVER_XE);
@@ -164,25 +166,38 @@ igt_main
 		sys_fd = igt_sysfs_open(fd);
 		igt_require(sys_fd != -1);
 		close(sys_fd);
+
+		xe_for_each_gt(fd, gt) {
+			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_assert(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);
+					igt_sysfs_engines(fd, engines_fd[j], gt, 1, property[i],
+										    t->fn);
+					j++;
 				}
 			}
 		}
 	}
 	igt_fixture {
+		for (int i = gt_count - 1; i >= 0; i--) {
+			set_timeslice_duration(engines_fd[i], tds[i]);
+			close(engines_fd[i]);
+			close(gt_fd[i]);
+		}
 		drm_close_driver(fd);
 	}
 }
-- 
2.43.0