[Intel-gfx] [PATCH i-g-t 4/4] tests/gem_media_vme: Shut down half of subslices to avoid gpu hang on ICL

[Tvrtko Ursulin]

From: Tony Ye <tony.ye at intel.com>

On Icelake we need to turn off subslices not containing the VME block or
the VME kernel will hang.

v2: (Tvrtko Ursulin)
 * Remove libdrm usage for setting context param.
 * Cleanup bitmask operation.
 * Only apply the workaround for ICL.

v3: (Tvrtko Ursulin)
 * Added hang detector. (Chris Wilson)

v4: (Tvrtko Ursulin)
 * Rebase for hang detector moved to previous patch.
 * Tidy curly braces.

Signed-off-by: Tony Ye <tony.ye at intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Tony Ye <tony.ye at intel.com>
---
 lib/gpu_cmds.c             | 12 ++++++++
 lib/gpu_cmds.h             |  3 ++
 lib/media_fill.c           |  2 +-
 tests/i915/gem_media_vme.c | 60 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/lib/gpu_cmds.c b/lib/gpu_cmds.c
index b490a63bdfef..8d270ee86229 100644
--- a/lib/gpu_cmds.c
+++ b/lib/gpu_cmds.c
@@ -36,6 +36,18 @@ gen7_render_flush(struct intel_batchbuffer *batch, uint32_t batch_end)
 	igt_assert(ret == 0);
 }
 
+void
+gen7_render_context_flush(struct intel_batchbuffer *batch, uint32_t batch_end)
+{
+	int ret;
+
+	ret = drm_intel_bo_subdata(batch->bo, 0, 4096, batch->buffer);
+	if (ret == 0)
+		ret = drm_intel_gem_bo_context_exec(batch->bo, batch->ctx,
+				batch_end, 0);
+	igt_assert(ret == 0);
+}
+
 uint32_t
 gen7_fill_curbe_buffer_data(struct intel_batchbuffer *batch,
 			    uint8_t color)
diff --git a/lib/gpu_cmds.h b/lib/gpu_cmds.h
index ca671fb52daf..1321af446161 100644
--- a/lib/gpu_cmds.h
+++ b/lib/gpu_cmds.h
@@ -40,6 +40,9 @@
 void
 gen7_render_flush(struct intel_batchbuffer *batch, uint32_t batch_end);
 
+void
+gen7_render_context_flush(struct intel_batchbuffer *batch, uint32_t batch_end);
+
 uint32_t
 gen7_fill_curbe_buffer_data(struct intel_batchbuffer *batch,
 			uint8_t color);
diff --git a/lib/media_fill.c b/lib/media_fill.c
index b1e84727394a..03b5e71e101b 100644
--- a/lib/media_fill.c
+++ b/lib/media_fill.c
@@ -338,7 +338,7 @@ __gen11_media_vme_func(struct intel_batchbuffer *batch,
 	batch_end = intel_batchbuffer_align(batch, 8);
 	assert(batch_end < BATCH_STATE_SPLIT);
 
-	gen7_render_flush(batch, batch_end);
+	gen7_render_context_flush(batch, batch_end);
 	intel_batchbuffer_reset(batch);
 }
 
diff --git a/tests/i915/gem_media_vme.c b/tests/i915/gem_media_vme.c
index 47e949c781f2..34383cb123d4 100644
--- a/tests/i915/gem_media_vme.c
+++ b/tests/i915/gem_media_vme.c
@@ -81,6 +81,52 @@ static void scratch_buf_init_dst(drm_intel_bufmgr *bufmgr, struct igt_buf *buf)
 	buf->stride = 1;
 }
 
+static uint64_t switch_off_n_bits(uint64_t mask, unsigned int n)
+{
+	unsigned int i;
+
+	igt_assert(n > 0 && n <= (sizeof(mask) * 8));
+	igt_assert(n <= __builtin_popcount(mask));
+
+	for (i = 0; n && i < (sizeof(mask) * 8); i++) {
+		uint64_t bit = 1ULL << i;
+
+		if (bit & mask) {
+			mask &= ~bit;
+			n--;
+		}
+	}
+
+	return mask;
+}
+
+static void shut_non_vme_subslices(int drm_fd, uint32_t ctx)
+{
+	struct drm_i915_gem_context_param_sseu sseu = { };
+	struct drm_i915_gem_context_param arg = {
+		.param = I915_CONTEXT_PARAM_SSEU,
+		.ctx_id = ctx,
+		.size = sizeof(sseu),
+		.value = to_user_pointer(&sseu),
+	};
+	int ret;
+
+	if (__gem_context_get_param(drm_fd, &arg))
+		return; /* no sseu support */
+
+	ret = __gem_context_set_param(drm_fd, &arg);
+	igt_assert(ret == 0 || ret == -ENODEV || ret == -EINVAL);
+	if (ret)
+		return; /* no sseu support */
+
+	/* shutdown half subslices*/
+	sseu.subslice_mask =
+		switch_off_n_bits(sseu.subslice_mask,
+				  __builtin_popcount(sseu.subslice_mask) / 2);
+
+	gem_context_set_param(drm_fd, &arg);
+}
+
 igt_simple_main
 {
 	int drm_fd;
@@ -108,6 +154,20 @@ igt_simple_main
 	scratch_buf_init_src(bufmgr, &src);
 	scratch_buf_init_dst(bufmgr, &dst);
 
+	batch->ctx = drm_intel_gem_context_create(bufmgr);
+	igt_assert(batch->ctx);
+
+	/* ICL hangs if non-VME enabled slices are enabled with a VME kernel. */
+	if (intel_gen(devid) == 11) {
+		uint32_t ctx_id;
+		int ret;
+
+		ret = drm_intel_gem_context_get_id(batch->ctx, &ctx_id);
+		igt_assert_eq(ret, 0);
+
+		shut_non_vme_subslices(drm_fd, ctx_id);
+	}
+
 	igt_fork_hang_detector(drm_fd);
 
 	media_vme(batch, &src, WIDTH, HEIGHT, &dst);
-- 
2.19.1