[i-g-t][PATCH 2/2] kms_flip: Add flip-vs-modeset-vs-hang test

[ville.syrjala@linux.intel.com]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

The flip-vs-modeset-vs-hang test will:
1. simulate a GPU hang
2. exec a nop batch
3. schedule a page flip
4. perform a modeset operation

With the current buggy kernel driver, the modeset operation will
hang indefinitely waiting for the flip to complete. Since the
rings are stopped, that will never happen. The current GPU reset
code doesn't play well with page flips either, so a GPU reset
won't fix things.

Once the kernel driver is fixed, the eventual GPU reset will
save the day.

The nop batch buffer is required only because the kernel can't
currently detect GPU hangs, unless there is at least one user
submitted request pending.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 tests/kms_flip.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 86 insertions(+), 2 deletions(-)

diff --git a/tests/kms_flip.c b/tests/kms_flip.c
index 97bd145..c2a29ae 100644
--- a/tests/kms_flip.c
+++ b/tests/kms_flip.c
@@ -26,6 +26,7 @@
 #include <assert.h>
 #include <cairo.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <math.h>
 #include <stdint.h>
 #include <unistd.h>
@@ -55,6 +56,7 @@
 #define TEST_VBLANK_EXPIRED_SEQ	(1 << 11)
 #define TEST_FB_RECREATE	(1 << 12)
 #define TEST_RMFB		(1 << 13)
+#define TEST_HANG		(1 << 14)
 
 #define EVENT_FLIP		(1 << 0)
 #define EVENT_VBLANK		(1 << 1)
@@ -493,6 +495,75 @@ static void recreate_fb(struct test_output *o)
 	o->fb_info[o->current_fb_id].fb_id = new_fb_id;
 }
 
+static int exec_nop(int fd, uint32_t handle)
+{
+	struct drm_i915_gem_execbuffer2 execbuf;
+	struct drm_i915_gem_exec_object2 gem_exec[1];
+	uint32_t b[2] = {MI_BATCH_BUFFER_END};
+	int r;
+
+	gem_write(fd, handle, 0, b, sizeof(b));
+
+	gem_exec[0].handle = handle;
+	gem_exec[0].relocation_count = 0;
+	gem_exec[0].relocs_ptr = 0;
+	gem_exec[0].alignment = 0;
+	gem_exec[0].offset = 0;
+	gem_exec[0].flags = 0;
+	gem_exec[0].rsvd1 = 0;
+	gem_exec[0].rsvd2 = 0;
+
+	execbuf.buffers_ptr = (uintptr_t)gem_exec;
+	execbuf.buffer_count = 1;
+	execbuf.batch_start_offset = 0;
+	execbuf.batch_len = 8;
+	execbuf.cliprects_ptr = 0;
+	execbuf.num_cliprects = 0;
+	execbuf.DR1 = 0;
+	execbuf.DR4 = 0;
+	execbuf.flags =  I915_EXEC_RENDER;
+	i915_execbuffer2_set_context_id(execbuf, 0);
+	execbuf.rsvd2 = 0;
+
+	r = drmIoctl(fd,
+			DRM_IOCTL_I915_GEM_EXECBUFFER2,
+			&execbuf);
+	if (r)
+		fprintf(stderr, "failed to exec: %s\n",
+			strerror(errno));
+	return r;
+}
+
+static void hang_gpu(struct test_output *o)
+{
+	static const char dfs_base[] = "/sys/kernel/debug/dri";
+	static const char dfs_entry[] = "i915_ring_stop";
+	static const char data[] = "0xf";
+	char fname[FILENAME_MAX];
+	int card_index = drm_get_card(0);
+	int fd;
+	ssize_t r;
+
+	assert(card_index != -1);
+
+	snprintf(fname, FILENAME_MAX, "%s/%i/%s",
+		 dfs_base, card_index, dfs_entry);
+
+	fd = open(fname, O_WRONLY);
+	if (fd < 0) {
+		fprintf(stderr, "failed to open '%s': %s\n",
+			fname, strerror(errno));
+		return;
+	}
+
+	r = write(fd, data, sizeof data);
+	if (r < 0)
+		fprintf(stderr, "failed to write '%s': %s\n",
+			fname, strerror(errno));
+
+	close(fd);
+}
+
 /* Return mask of completed events. */
 static unsigned int run_test_step(struct test_output *o)
 {
@@ -504,6 +575,7 @@ static unsigned int run_test_step(struct test_output *o)
 	bool do_vblank;
 	struct vblank_reply vbl_reply;
 	unsigned int target_seq;
+	uint32_t handle;
 
 	target_seq = o->vblank_state.seq_step;
 	if (o->flags & TEST_VBLANK_ABSOLUTE)
@@ -566,8 +638,14 @@ static unsigned int run_test_step(struct test_output *o)
 
 	printf("."); fflush(stdout);
 
+	if (do_flip && (o->flags & TEST_HANG)) {
+		handle = gem_create(drm_fd, 4096);
+		hang_gpu(o);
+		exec_nop(drm_fd, handle);
+	}
+
 	if (do_flip)
-		do_or_die(do_page_flip(o, new_fb_id, true));
+		do_or_die(do_page_flip(o, new_fb_id, !(o->flags & TEST_HANG)));
 
 	if (do_vblank) {
 		do_or_die(do_wait_for_vblank(o, o->pipe, target_seq,
@@ -623,6 +701,11 @@ static unsigned int run_test_step(struct test_output *o)
 	if (do_flip && (o->flags & TEST_EINVAL))
 		assert(do_page_flip(o, new_fb_id, true) == expected_einval);
 
+	if (do_flip && (o->flags & TEST_HANG)) {
+		gem_sync(drm_fd, handle);
+		gem_close(drm_fd, handle);
+	}
+
 	return completed_events;
 }
 
@@ -922,7 +1005,7 @@ static void run_test_on_crtc(struct test_output *o, int crtc, int duration)
 
 	ellapsed = event_loop(o, duration);
 
-	if (o->flags & TEST_FLIP)
+	if (o->flags & TEST_FLIP && !(o->flags & TEST_HANG))
 		check_final_state(o, &o->flip_state, ellapsed);
 	if (o->flags & TEST_VBLANK)
 		check_final_state(o, &o->vblank_state, ellapsed);
@@ -1025,6 +1108,7 @@ int main(int argc, char **argv)
 					"flip-vs-wf_vblank" },
 		{ 15, TEST_FLIP | TEST_VBLANK | TEST_VBLANK_BLOCK |
 			TEST_CHECK_TS, "flip-vs-blocking-wf-vblank" },
+		{ 15, TEST_FLIP | TEST_MODESET | TEST_HANG , "flip-vs-modeset-vs-hang" },
 	};
 	int i;
 
-- 
1.7.12.4

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