1 files changed, 85 insertions, 1 deletions
diff --git a/lib/igt_psr.c b/lib/igt_psr.c
index c979b0b5..bc142632 100644
--- a/lib/igt_psr.c
+++ b/lib/igt_psr.c
@@ -21,7 +21,9 @@
  * IN THE SOFTWARE.
  */
 
-#include  "igt_psr.h"
+#include "igt_psr.h"
+#include "igt_sysfs.h"
+#include <errno.h>
 
 bool psr_active(int fd, bool check_active)
 {
@@ -38,3 +40,85 @@ bool psr_wait_entry(int fd)
 {
 	return igt_wait(psr_active(fd, true), 500, 1);
 }
+
+static ssize_t psr_write(int fd, const char *buf)
+{
+	return igt_sysfs_write(fd, "i915_edp_psr_debug", buf, strlen(buf));
+}
+
+static int has_psr_debugfs(int fd)
+{
+	int ret;
+
+	/*
+	 * Check if new PSR debugfs api is usable by writing an invalid value.
+	 * Legacy mode will return OK here, debugfs api will return -EINVAL.
+	 * -ENODEV is returned when PSR is unavailable.
+	 */
+	ret = psr_write(fd, "0xf");
+	if (ret == -EINVAL)
+		return 0;
+	else if (ret < 0)
+		return ret;
+
+	/* legacy debugfs api, we enabled irqs by writing, disable them. */
+	psr_write(fd, "0");
+	return -EINVAL;
+}
+
+static bool psr_modparam_set(int val)
+{
+	static int oldval = -1;
+
+	igt_set_module_param_int("enable_psr", val);
+
+	if (val == oldval)
+		return false;
+
+	oldval = val;
+	return true;
+}
+
+static int psr_restore_debugfs_fd = -1;
+
+static void restore_psr_debugfs(int sig)
+{
+	psr_write(psr_restore_debugfs_fd, "0");
+}
+
+static bool psr_set(int fd, bool enable)
+{
+	int ret;
+
+	ret = has_psr_debugfs(fd);
+	if (ret == -ENODEV) {
+		igt_skip_on_f(enable, "PSR not available\n");
+		return false;
+	}
+
+	if (ret == -EINVAL) {
+		ret = psr_modparam_set(enable);
+	} else {
+		ret = psr_write(fd, enable ? "0x3" : "0x1");
+		igt_assert(ret > 0);
+	}
+
+	/* Restore original value on exit */
+	if (psr_restore_debugfs_fd == -1) {
+		psr_restore_debugfs_fd = dup(fd);
+		igt_assert(psr_restore_debugfs_fd >= 0);
+		igt_install_exit_handler(restore_psr_debugfs);
+	}
+
+	return ret;
+}
+
+bool psr_enable(int fd)
+{
+	return psr_set(fd, true);
+}
+
+bool psr_disable(int fd)
+{
+	return psr_set(fd, false);
+}