[igt-dev] [PATCH i-g-t v2] tests/gen7_forcewake_mt: Fix test

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

1.
We need to tell the compiler mmio access cannot be optimized away
(volatile).

2.
We need to ensure we don't exit with forcewake left on. Signal threads
to exit in a controlled fashion and install atexit handler just in case.

v2: Do not assert from the threads.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 tests/gen7_forcewake_mt.c | 68 +++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 63 insertions(+), 5 deletions(-)

diff --git a/tests/gen7_forcewake_mt.c b/tests/gen7_forcewake_mt.c
index 07320ef9e8ac..608217fe652a 100644
--- a/tests/gen7_forcewake_mt.c
+++ b/tests/gen7_forcewake_mt.c
@@ -44,6 +44,7 @@ IGT_TEST_DESCRIPTION("Exercise a suspect workaround required for"
 
 struct thread {
 	pthread_t thread;
+	bool run;
 	void *mmio;
 	int fd;
 	int bit;
@@ -106,14 +107,26 @@ static void *igfx_get_mmio(void)
 static void *thread(void *arg)
 {
 	struct thread *t = arg;
-	uint32_t *forcewake_mt = (uint32_t *)((char *)t->mmio + FORCEWAKE_MT);
+	volatile uint32_t *forcewake_mt =
+		(uint32_t *)((char *)t->mmio + FORCEWAKE_MT);
 	uint32_t bit = 1 << t->bit;
 
-	while (1) {
+	while (t->run) {
+		uint32_t reg;
+
 		*forcewake_mt = bit << 16 | bit;
-		igt_assert(*forcewake_mt & bit);
+		reg = *forcewake_mt;
+		if (!(reg & bit)) {
+			igt_warn("Bit %u did not set! (val=%x)\n", t->bit, reg);
+			return (void *)-1;
+		}
 		*forcewake_mt = bit << 16;
-		igt_assert((*forcewake_mt & bit) == 0);
+		reg = *forcewake_mt;
+		if (reg & bit) {
+			igt_warn("Bit %u did not clear! (val=%x)\n",
+				 t->bit, reg);
+			return (void *)-1;
+		}
 	}
 
 	return NULL;
@@ -121,13 +134,39 @@ static void *thread(void *arg)
 
 #define MI_STORE_REGISTER_MEM                   (0x24<<23)
 
+static void *mmio_base;
+
+static void cleanup(int sig)
+{
+	volatile uint32_t *forcewake_mt =
+		(uint32_t *)((char *)mmio_base + FORCEWAKE_MT);
+	unsigned int bit;
+
+	for (bit = 2; bit < 16; bit++) {
+		uint32_t val = 1 << bit;
+		uint32_t reg;
+
+		*forcewake_mt = val << 16;
+		reg = *forcewake_mt;
+		if (reg & val)
+			igt_warn("Failed to restore bit %u! (val=%x)\n",
+				 bit, reg);
+	}
+}
+
 igt_simple_main
 {
 	struct thread t[16];
+	bool success = true;
 	int i;
 
+	mmio_base = igfx_get_mmio();
+
 	t[0].fd = drm_open_driver(DRIVER_INTEL);
-	t[0].mmio = igfx_get_mmio();
+	t[0].run = true;
+	t[0].mmio = mmio_base;
+
+	igt_install_exit_handler(cleanup);
 
 	for (i = 2; i < 16; i++) {
 		t[i] = t[0];
@@ -201,4 +240,23 @@ igt_simple_main
 
 		usleep(1000);
 	}
+
+	for (i = 2; i < 16; i++)
+		t[i].run = false;
+
+	for (i = 2; i < 16; i++) {
+		void *threadret = NULL;
+		int ret;
+
+		ret = pthread_join(t[i].thread, &threadret);
+		if (ret) {
+			igt_warn("failed to join thread%u! (%d)\n", i, ret);
+			success = false;
+		} else if (threadret) {
+			igt_warn("thread%u failed! (%p)\n", i, threadret);
+			success = false;
+		}
+	}
+
+	igt_assert(success);
 }
-- 
2.14.1