lib/igt_pm: Lib for power management

Move power management related code to a separate library.
Initially this is done only for workarounds that apply to external
components.  Modify the users of such workarounds accordingly.
This currently involves HD audio and SATA link power management.
For SATA link PM there's also code to save the previous settings,
to allow for resetting the values after we've finished testing.

Signed-off-by: David Weinehall <david.weinehall@intel.com>
Reviewed-by: Marius Vlad <marius.c.vlad@intel.com>
Signed-off-by: Marius Vlad <marius.c.vlad@intel.com>

1 files changed, 233 insertions, 0 deletions

diff --git a/lib/igt_pm.c b/lib/igt_pm.c
new file mode 100644
index 00000000..b1b5503c
--- /dev/null
+++ b/lib/igt_pm.c
@@ -0,0 +1,233 @@
+/*
+ * Copyright © 2013, 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Paulo Zanoni <paulo.r.zanoni@intel.com>
+ *    David Weinehall <david.weinehall@intel.com>
+ *
+ */
+#include <fcntl.h>
+#include <stdio.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "drmtest.h"
+#include "igt_pm.h"
+
+enum {
+	POLICY_UNKNOWN = -1,
+	POLICY_MAX_PERFORMANCE = 0,
+	POLICY_MEDIUM_POWER = 1,
+	POLICY_MIN_POWER = 2
+};
+
+#define MAX_PERFORMANCE_STR	"max_performance\n"
+#define MEDIUM_POWER_STR	"medium_power\n"
+#define MIN_POWER_STR		"min_power\n"
+/* Remember to fix this if adding longer strings */
+#define MAX_POLICY_STRLEN	strlen(MAX_PERFORMANCE_STR)
+
+/**
+ * SECTION:igt_pm
+ * @short_description: Power Management related helpers
+ * @title: Power Management
+ * @include: igt.h
+ *
+ * This library provides various helpers to enable power management for,
+ * and in some cases subsequently allow restoring the old behaviour of,
+ * various external components that by default are set up in a way
+ * that interferes with the testing of our power management functionality.
+ */
+/**
+ * igt_pm_enable_audio_runtime_pm:
+ *
+ * We know that if we don't enable audio runtime PM, snd_hda_intel will never
+ * release its power well refcount, and we'll never reach the LPSP state.
+ * There's no guarantee that it will release the power well if we enable
+ * runtime PM, but at least we can try.
+ *
+ * We don't have any assertions on open since the user may not even have
+ * snd_hda_intel loaded, which is not a problem.
+ */
+void igt_pm_enable_audio_runtime_pm(void)
+{
+	int fd;
+
+	fd = open("/sys/module/snd_hda_intel/parameters/power_save", O_WRONLY);
+	if (fd >= 0) {
+		igt_assert_eq(write(fd, "1\n", 2), 2);
+		close(fd);
+	}
+	fd = open("/sys/bus/pci/devices/0000:00:03.0/power/control", O_WRONLY);
+	if (fd >= 0) {
+		igt_assert_eq(write(fd, "auto\n", 5), 5);
+		close(fd);
+	}
+	/* Give some time for it to react. */
+	sleep(1);
+}
+
+/**
+ * igt_pm_enable_sata_link_power_management:
+ *
+ * Enable the min_power policy for SATA link power management.
+ * Without this we cannot reach deep runtime power states.
+ *
+ * We don't have any assertions on open since the system might not have
+ * a SATA host.
+ *
+ * Returns:
+ * An opaque pointer to the data needed to restore the default values
+ * after the test has terminated, or NULL if SATA link power management
+ * is not supported. This pointer should be freed when no longer used
+ * (typically after having called restore_sata_link_power_management()).
+ */
+int8_t *igt_pm_enable_sata_link_power_management(void)
+{
+	int fd, i;
+	ssize_t len;
+	char *buf;
+	char *file_name;
+	int8_t *link_pm_policies = NULL;
+
+	file_name = malloc(PATH_MAX);
+	buf = malloc(MAX_POLICY_STRLEN + 1);
+
+	for (i = 0; ; i++) {
+		int8_t policy;
+
+		snprintf(file_name, PATH_MAX,
+			 "/sys/class/scsi_host/host%d/link_power_management_policy",
+			 i);
+
+		fd = open(file_name, O_RDWR);
+		if (fd < 0)
+			break;
+
+		len = read(fd, buf, MAX_POLICY_STRLEN);
+		buf[len] = '\0';
+
+		if (!strncmp(MAX_PERFORMANCE_STR, buf,
+			     strlen(MAX_PERFORMANCE_STR)))
+			policy = POLICY_MAX_PERFORMANCE;
+		else if (!strncmp(MEDIUM_POWER_STR, buf,
+				  strlen(MEDIUM_POWER_STR)))
+			policy = POLICY_MEDIUM_POWER;
+		else if (!strncmp(MIN_POWER_STR, buf,
+				  strlen(MIN_POWER_STR)))
+			policy = POLICY_MIN_POWER;
+		else
+			policy = POLICY_UNKNOWN;
+
+		if (!(i % 256))
+			link_pm_policies = realloc(link_pm_policies,
+						   (i / 256 + 1) * 256 + 1);
+
+		link_pm_policies[i] = policy;
+		link_pm_policies[i + 1] = 0;
+
+		/* If the policy is something we don't know about,
+		 * don't touch it, since we might potentially break things.
+		 * And we obviously don't need to touch anything if the
+		 * setting is already correct...
+		 */
+		if (policy != POLICY_UNKNOWN &&
+		    policy != POLICY_MIN_POWER) {
+			lseek(fd, 0, SEEK_SET);
+			igt_assert_eq(write(fd, MIN_POWER_STR,
+					    strlen(MIN_POWER_STR)),
+				      strlen(MIN_POWER_STR));
+		}
+		close(fd);
+	}
+	free(buf);
+	free(file_name);
+
+	return link_pm_policies;
+}
+
+/**
+ * igt_pm_restore_sata_link_power_management:
+ * @pm_data: An opaque pointer with saved link PM policies;
+ *           If NULL is passed we force enable the "max_performance" policy.
+ *
+ * Restore the link power management policies to the values
+ * prior to enabling min_power.
+ *
+ * Caveat: If the system supports hotplugging and hotplugging takes
+ *         place during our testing so that the hosts change numbers
+ *         we might restore the settings to the wrong hosts.
+ */
+void igt_pm_restore_sata_link_power_management(int8_t *pm_data)
+{
+	int fd, i;
+	char *file_name;
+
+	/* Disk runtime PM policies. */
+	file_name = malloc(PATH_MAX);
+	for (i = 0; ; i++) {
+		int8_t policy;
+
+		if (!pm_data)
+			policy = POLICY_MAX_PERFORMANCE;
+		else if (pm_data[i] == POLICY_UNKNOWN)
+			continue;
+		else
+			policy = pm_data[i];
+
+		snprintf(file_name, PATH_MAX,
+			 "/sys/class/scsi_host/host%d/link_power_management_policy",
+			 i);
+
+		fd = open(file_name, O_WRONLY);
+		if (fd < 0)
+			break;
+
+		switch (policy) {
+		default:
+		case POLICY_MAX_PERFORMANCE:
+			igt_assert_eq(write(fd, MAX_PERFORMANCE_STR,
+					    strlen(MAX_PERFORMANCE_STR)),
+				      strlen(MAX_PERFORMANCE_STR));
+			break;
+
+		case POLICY_MEDIUM_POWER:
+			igt_assert_eq(write(fd, MEDIUM_POWER_STR,
+					    strlen(MEDIUM_POWER_STR)),
+				      strlen(MEDIUM_POWER_STR));
+			break;
+
+		case POLICY_MIN_POWER:
+			igt_assert_eq(write(fd, MIN_POWER_STR,
+					    strlen(MIN_POWER_STR)),
+				      strlen(MIN_POWER_STR));
+			break;
+		}
+
+		close(fd);
+	}
+	free(file_name);
+}