[Intel-gfx] [PATCH 4/4] pm_rps: Require that cur reaches min at idle

[jeff . mcgee]

From: Jeff McGee <jeff.mc...@intel.com>

The current frequency should reach the minimum frequency within a
reasonable time during idle. We hold forcewake to prevent interference
from sleep states.

Signed-off-by: Jeff McGee <jeff.mc...@intel.com>
---
 tests/pm_rps.c | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/tests/pm_rps.c b/tests/pm_rps.c
index 7ae0438..50c66ee 100644
--- a/tests/pm_rps.c
+++ b/tests/pm_rps.c
@@ -33,6 +33,7 @@
 #include <unistd.h>
 #include <getopt.h>
 #include "drmtest.h"
+#include "igt_debugfs.h"
 
 static bool verbose = false;
 
@@ -57,6 +58,9 @@ struct junk {
        { "cur", "r", NULL }, { "min", "rb+", NULL }, { "max", "rb+", NULL }, { 
"RP0", "r", NULL }, { "RP1", "r", NULL }, { "RPn", "r", NULL }, { NULL, NULL, 
NULL }
 };
 
+static igt_debugfs_t dfs;
+static FILE *forcewake;
+
 static int readval(FILE *filp)
 {
        int val;
@@ -206,17 +210,33 @@ static void min_max_config(void (*check)(void))
        check();
 }
 
+#define IDLE_WAIT_TIMESTEP_MSEC 100
+#define IDLE_WAIT_TIMEOUT_MSEC 3000
 static void idle_check(void)
 {
        int freqs[NUMFREQ];
-
-       read_freqs(freqs);
-       dump(freqs);
-       checkit(freqs);
+       int wait = 0;
+
+       /* Monitor frequencies until cur settles down to min, which should
+        * happen within the allotted time */
+       do {
+               read_freqs(freqs);
+               dump(freqs);
+               checkit(freqs);
+               if (freqs[CUR] == freqs[MIN])
+                       break;
+               usleep(1000 * IDLE_WAIT_TIMESTEP_MSEC);
+               wait += IDLE_WAIT_TIMESTEP_MSEC;
+       } while (wait < IDLE_WAIT_TIMEOUT_MSEC);
+
+       igt_assert(freqs[CUR] == freqs[MIN]);
+       log("Required %d msec to reach cur=min\n", wait);
 }
 
 static void pm_rps_exit_handler(int sig)
 {
+       fclose(forcewake);
+
        if (origfreqs[MIN] > readval(stuff[MAX].filp)) {
                writeval(stuff[MAX].filp, origfreqs[MAX]);
                writeval(stuff[MIN].filp, origfreqs[MIN]);
@@ -287,6 +307,12 @@ int main(int argc, char **argv)
 
                read_freqs(origfreqs);
 
+               /* Hold forcewake throughout test to prevent sleep states from
+                * interfering with evaluation of performance state management 
*/
+               igt_require(igt_debugfs_init(&dfs) == 0);
+               forcewake = igt_debugfs_fopen(&dfs, "i915_forcewake_user", "r");
+               igt_require(forcewake);
+
                igt_install_exit_handler(pm_rps_exit_handler);
        }
 
-- 
1.8.5.2

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