[igt-dev] [PATCH i-g-t v7 2/2] tests/i915/i915_pm_dc: Fix DC9 test

[Jigar Bhatt <jigar.bhatt@intel.com>]

Fixing DC9 test with reading prev_dc counter(DC5/DC6),
comparing to actual counter values.
Dumping i915_pm_runtime_status debugfs incase of failure.
While executing test, it require to disable the kms connector polling
to avoid runtime resume.
This would require to save and restore the kms connector poll state.

V1: Reading previous DC counter
prev_dc = read_dc_counter(dc_target) before the dpms_off().

V2: Bit cleaner code.[Imre]
dump the i915_pm_runtime_status debugfs file in case of test
failure.[Anshuman]

V3: Disabling the polling during DC9 test “echo 0 >
/sys/module/drm_kms_helper/parameters/poll”.[Anshuman]

V4: Passing right fd to igt_sysfs_get_boolean() function,
moving save and get part of polling to setup_dc9_dpms().

V5: Use macro for "/sys/module/drm_kms_helper/parameters/poll".
Add igt_require when opening sysfs.
Add igt_install_exit_handler(reset_kms_poll) so it will restore actual
sysfs kms polling status.[Anshuman]

V6: Using if() condition instead of
igt_require((sysfs_fd = open(KMS_POLL_PATH, O_WRONLY)) >= 0)
[Petri]

V7: KMS_HELPER "/sys/module/drm_kms_helper/parameters/ " for opening
the sys_fd and then use it in igt_sysfs_get_boolean()
along with "poll", attribute as per the API doc.[Anshuman]

Signed-off-by: Jigar Bhatt <jigar.bhatt@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
---
 tests/i915/i915_pm_dc.c | 54 ++++++++++++++++++++++++++++++-----------
 1 file changed, 40 insertions(+), 14 deletions(-)

diff --git a/tests/i915/i915_pm_dc.c b/tests/i915/i915_pm_dc.c
index 04acf839..d70ee060 100644
--- a/tests/i915/i915_pm_dc.c
+++ b/tests/i915/i915_pm_dc.c
@@ -40,6 +40,11 @@
 #define CHECK_DC3CO	(1 << 2)
 
 #define PWR_DOMAIN_INFO "i915_power_domain_info"
+#define RPM_STATUS "i915_runtime_pm_status"
+#define KMS_HELPER "/sys/module/drm_kms_helper/parameters/"
+#define KMS_POLL_DISABLE 0
+
+bool kms_poll_saved_state;
 
 typedef struct {
 	double r, g, b;
@@ -393,23 +398,35 @@ static bool support_dc6(int debugfs_fd)
 	return strstr(buf, "DC5 -> DC6 count");
 }
 
-static bool check_dc9(uint32_t debugfs_fd, int prev_dc, bool dc6_supported, int seconds)
+static bool dc9_wait_entry(uint32_t debugfs_fd, int dc_target, int prev_dc, int seconds)
 {
 	/*
 	 * since we do not have DC9 counter,
 	 * so we rely on dc5/dc6 counter reset to check if display engine was in DC9.
 	 */
-	return igt_wait(dc6_supported ? read_dc_counter(debugfs_fd, CHECK_DC6) <
-			prev_dc : read_dc_counter(debugfs_fd, CHECK_DC5) <
+	return igt_wait(read_dc_counter(debugfs_fd, dc_target) >
 			prev_dc, seconds, 100);
 }
 
-static void setup_dc9_dpms(data_t *data, int prev_dc, bool dc6_supported)
+static void check_dc9(data_t *data, int dc_target, int prev_dc)
 {
+	igt_assert_f(dc9_wait_entry(data->debugfs_fd, dc_target, prev_dc, 3000),
+			"DC9 state is not achieved\n%s:\n%s\n", RPM_STATUS,
+			data->debugfs_dump = igt_sysfs_get(data->debugfs_fd, RPM_STATUS));
+}
+
+static void setup_dc9_dpms(data_t *data, int dc_target)
+{
+	int prev_dc, sysfs_fd;
+
+	igt_require((sysfs_fd = open(KMS_HELPER, O_RDWR)) >= 0);
+	kms_poll_saved_state = igt_sysfs_get_boolean(sysfs_fd, "poll");
+	igt_sysfs_set_boolean(sysfs_fd, "poll", KMS_POLL_DISABLE);
+	close(sysfs_fd);
+	prev_dc = read_dc_counter(data->debugfs_fd, dc_target);
 	setup_dc_dpms(data);
 	dpms_off(data);
-	igt_skip_on_f(!(igt_wait(dc6_supported ? read_dc_counter(data->debugfs_fd, CHECK_DC6) >
-				prev_dc : read_dc_counter(data->debugfs_fd, CHECK_DC5) >
+	igt_skip_on_f(!(igt_wait(read_dc_counter(data->debugfs_fd, dc_target) >
 				prev_dc, 3000, 100)), "Unable to enters shallow DC states\n");
 	dpms_on(data);
 	cleanup_dc_dpms(data);
@@ -417,20 +434,28 @@ static void setup_dc9_dpms(data_t *data, int prev_dc, bool dc6_supported)
 
 static void test_dc9_dpms(data_t *data)
 {
-	bool dc6_supported;
+	int prev_dc, dc_target;
 
 	require_dc_counter(data->debugfs_fd, CHECK_DC5);
-	dc6_supported = support_dc6(data->debugfs_fd);
-	setup_dc9_dpms(data, dc6_supported ? read_dc_counter(data->debugfs_fd, CHECK_DC6) :
-			read_dc_counter(data->debugfs_fd, CHECK_DC5), dc6_supported);
+	dc_target = support_dc6(data->debugfs_fd) ? CHECK_DC6 : CHECK_DC5;
+	setup_dc9_dpms(data, dc_target);
+	prev_dc = read_dc_counter(data->debugfs_fd, dc_target);
 	dpms_off(data);
-	igt_assert_f(check_dc9(data->debugfs_fd, dc6_supported ?
-				read_dc_counter(data->debugfs_fd, CHECK_DC6) :
-				read_dc_counter(data->debugfs_fd, CHECK_DC5),
-				dc6_supported, 3000), "Not in DC9\n");
+	check_dc9(data, dc_target, prev_dc);
 	dpms_on(data);
 }
 
+static void kms_poll_state_restore(int sig)
+{
+	int sysfs_fd;
+
+	sysfs_fd = open(KMS_HELPER, O_WRONLY);
+	if (sysfs_fd >= 0) {
+		igt_sysfs_set_boolean(sysfs_fd, "poll", kms_poll_saved_state);
+		close(sysfs_fd);
+	}
+}
+
 IGT_TEST_DESCRIPTION("These tests validate Display Power DC states");
 int main(int argc, char *argv[])
 {
@@ -453,6 +478,7 @@ int main(int argc, char *argv[])
 		data.msr_fd = open("/dev/cpu/0/msr", O_RDONLY);
 		igt_assert_f(data.msr_fd >= 0,
 			     "Can't open /dev/cpu/0/msr.\n");
+		igt_install_exit_handler(kms_poll_state_restore);
 	}
 
 	igt_describe("In this test we make sure that system enters DC3CO "
-- 
2.25.1