kms_content_protection: uevent for HDCP status change

To detect the HDCP status change we are reading the uevent sent with the
corresponding connector id and property id.

This avoids the polling of the property every mSec.

v2:
  Made it as subtest. Remaining tests will use polling. [Daniel]
v3:
  failure to receive the uevent is handled as failure [Uma]
v4:
  For UNDESIRED state no uevent is expected.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/315470/?series=57756&rev=10

tests/kms_content_protection.c

@@ -24,6 +24,9 @@
 
 #include <poll.h>
 #include <fcntl.h>
+#include <sys/epoll.h>
+#include <sys/stat.h>
+#include <libudev.h>
 #include "igt.h"
 #include "igt_sysfs.h"
 #include "igt_kms.h"
@@ -43,6 +46,7 @@ struct data {
 #define CP_LIC					(1 << 1)
 #define CP_MEI_RELOAD				(1 << 2)
 #define CP_TYPE_CHANGE				(1 << 3)
+#define CP_UEVENT				(1 << 4)
 
 #define CP_UNDESIRED				0
 #define CP_DESIRED				1
@@ -102,6 +106,137 @@ static int wait_flip_event(void)
 	return rc;
 }
 
+static bool hdcp_event(struct udev_monitor *uevent_monitor,
+		       struct udev *udev, uint32_t conn_id, uint32_t prop_id)
+{
+	struct udev_device *dev;
+	dev_t udev_devnum;
+	struct stat s;
+	const char *hotplug, *connector, *property;
+	bool ret = false;
+
+	dev = udev_monitor_receive_device(uevent_monitor);
+	if (!dev)
+		goto out;
+
+	udev_devnum = udev_device_get_devnum(dev);
+	fstat(data.display.drm_fd, &s);
+
+	hotplug = udev_device_get_property_value(dev, "HOTPLUG");
+	if (!(memcmp(&s.st_rdev, &udev_devnum, sizeof(dev_t)) == 0 &&
+	    hotplug && atoi(hotplug) == 1)) {
+		igt_debug("Not a Hotplug event\n");
+		goto out_dev;
+	}
+
+	connector = udev_device_get_property_value(dev, "CONNECTOR");
+	if (!(memcmp(&s.st_rdev, &udev_devnum, sizeof(dev_t)) == 0 &&
+	    connector && atoi(connector) == conn_id)) {
+		igt_debug("Not for connector id: %u\n", conn_id);
+		goto out_dev;
+	}
+
+	property = udev_device_get_property_value(dev, "PROPERTY");
+	if (!(memcmp(&s.st_rdev, &udev_devnum, sizeof(dev_t)) == 0 &&
+	    property && atoi(property) == prop_id)) {
+		igt_debug("Not for property id: %u\n", prop_id);
+		goto out_dev;
+	}
+	ret = true;
+
+out_dev:
+	udev_device_unref(dev);
+out:
+	return ret;
+}
+
+static void hdcp_udev_fini(struct udev_monitor *uevent_monitor,
+			   struct udev *udev)
+{
+	if (uevent_monitor)
+		udev_monitor_unref(uevent_monitor);
+	if (udev)
+		udev_unref(udev);
+}
+
+static int hdcp_udev_init(struct udev_monitor *uevent_monitor,
+			  struct udev *udev)
+{
+	int ret = -EINVAL;
+
+	udev = udev_new();
+	if (!udev) {
+		igt_info("failed to create udev object\n");
+		goto out;
+	}
+
+	uevent_monitor = udev_monitor_new_from_netlink(udev, "udev");
+	if (!uevent_monitor) {
+		igt_info("failed to create udev event monitor\n");
+		goto out;
+	}
+
+	ret = udev_monitor_filter_add_match_subsystem_devtype(uevent_monitor,
+							      "drm",
+							      "drm_minor");
+	if (ret < 0) {
+		igt_info("failed to filter for drm events\n");
+		goto out;
+	}
+
+	ret = udev_monitor_enable_receiving(uevent_monitor);
+	if (ret < 0) {
+		igt_info("failed to enable udev event reception\n");
+		goto out;
+	}
+
+	return udev_monitor_get_fd(uevent_monitor);
+
+out:
+	hdcp_udev_fini(uevent_monitor, udev);
+	return ret;
+}
+
+#define MAX_EVENTS	10
+static bool wait_for_hdcp_event(uint32_t conn_id, uint32_t prop_id,
+				uint32_t timeout_mSec)
+{
+
+	struct udev_monitor *uevent_monitor = NULL;
+	struct udev *udev = NULL;
+	int udev_fd, epoll_fd;
+	struct epoll_event event, events[MAX_EVENTS];
+	bool ret = false;
+
+	udev_fd = hdcp_udev_init(uevent_monitor, udev);
+	if (udev_fd < 0)
+		return false;
+
+	epoll_fd = epoll_create1(0);
+	if (epoll_fd == -1) {
+		igt_info("Failed to create epoll fd. %d\n", epoll_fd);
+		goto out_ep_create;
+	}
+
+	event.events = EPOLLIN | EPOLLERR;
+	event.data.fd = 0;
+
+	if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, udev_fd, &event)) {
+		igt_info("failed to fd into epoll\n");
+		goto out_ep_ctl;
+	}
+
+	if (epoll_wait(epoll_fd, events, MAX_EVENTS, timeout_mSec))
+		ret = hdcp_event(uevent_monitor, udev, conn_id, prop_id);
+
+out_ep_ctl:
+	if (close(epoll_fd))
+		igt_info("failed to close the epoll fd\n");
+out_ep_create:
+	hdcp_udev_fini(uevent_monitor, udev);
+	return ret;
+}
+
 static bool
 wait_for_prop_value(igt_output_t *output, uint64_t expected,
 		    uint32_t timeout_mSec)
@@ -109,13 +244,25 @@ wait_for_prop_value(igt_output_t *output, uint64_t expected,
 	uint64_t val;
 	int i;
 
-	for (i = 0; i < timeout_mSec; i++) {
+	if (data.cp_tests & CP_UEVENT && expected != CP_UNDESIRED) {
+		igt_assert_f(wait_for_hdcp_event(output->id,
+			     output->props[IGT_CONNECTOR_CONTENT_PROTECTION],
+			     timeout_mSec), "uevent is not received");
+
 		val = igt_output_get_prop(output,
 					  IGT_CONNECTOR_CONTENT_PROTECTION);
 		if (val == expected)
 			return true;
-		usleep(1000);
+	} else {
+		for (i = 0; i < timeout_mSec; i++) {
+			val = igt_output_get_prop(output,
+						  IGT_CONNECTOR_CONTENT_PROTECTION);
+			if (val == expected)
+				return true;
+			usleep(1000);
+		}
 	}
+
 	igt_info("prop_value mismatch %" PRId64 " != %" PRId64 "\n",
 		 val, expected);
 
@@ -493,6 +640,12 @@ igt_main
 		test_content_protection(COMMIT_ATOMIC, HDCP_CONTENT_TYPE_1);
 	}
 
+	igt_subtest("uevent") {
+		igt_require(data.display.is_atomic);
+		data.cp_tests = CP_UEVENT;
+		test_content_protection(COMMIT_ATOMIC, HDCP_CONTENT_TYPE_0);
+	}
+
 	igt_fixture
 		igt_display_fini(&data.display);
 }