[Intel-gfx] [PATCH] drm/i915: track relative-constants-mode per-context not per-device

[Dave Gordon]

'relative_constants_mode' has always been tracked per-device, but this
is wrong in execlists (or GuC) mode, as INSTPM is saved and restored
with the logical context, and the per-context value could therefore get
out of sync with the tracked value. This patch moves the tracking
element from the dev_priv structure into the intel_context structure,
with corresponding adjustments to the code that initialises and uses it.

Test case (if anyone wants to write it) would be to create two contexts,
submit a batch with a non-default mode in the first context, submit a
batch with the default mode in the other context, submit another batch
in the first context, but this time in default mode. The driver will
fail to insert the instructions to reset INSTPM into the first context's
ringbuffer.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92448

Signed-off-by: Dave Gordon <david.s.gordon at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h            | 4 ++--
 drivers/gpu/drm/i915/i915_gem.c            | 2 --
 drivers/gpu/drm/i915/i915_gem_context.c    | 3 +++
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 6 +++---
 drivers/gpu/drm/i915/intel_lrc.c           | 6 +++---
 5 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 51eea29..2917370 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -872,6 +872,8 @@ struct intel_context {
 	struct i915_ctx_hang_stats hang_stats;
 	struct i915_hw_ppgtt *ppgtt;
 
+	int relative_constants_mode;
+
 	/* Legacy ring buffer submission */
 	struct {
 		struct drm_i915_gem_object *rcs_state;
@@ -1707,8 +1709,6 @@ struct drm_i915_private {
 
 	const struct intel_device_info info;
 
-	int relative_constants_mode;
-
 	void __iomem *regs;
 
 	struct intel_uncore uncore;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index f0cfbb9..374af2d 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4894,8 +4894,6 @@ i915_gem_load(struct drm_device *dev)
 			  i915_gem_idle_work_handler);
 	init_waitqueue_head(&dev_priv->gpu_error.reset_queue);
 
-	dev_priv->relative_constants_mode = I915_EXEC_CONSTANTS_REL_GENERAL;
-
 	if (INTEL_INFO(dev)->gen >= 7 && !IS_VALLEYVIEW(dev))
 		dev_priv->num_fence_regs = 32;
 	else if (INTEL_INFO(dev)->gen >= 4 || IS_I945G(dev) || IS_I945GM(dev) || IS_G33(dev))
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 74aa0c9..465e3e0 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -222,6 +222,9 @@ __create_hw_context(struct drm_device *dev,
 	 * is no remap info, it will be a NOP. */
 	ctx->remap_slice = (1 << NUM_L3_SLICES(dev)) - 1;
 
+	/* First execbuffer will override this */
+	ctx->relative_constants_mode = -1;
+
 	ctx->hang_stats.ban_period_seconds = DRM_I915_CTX_BAN_PERIOD;
 
 	return ctx;
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index edc17be..9833c8a 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1283,7 +1283,7 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
 			goto error;
 		}
 
-		if (instp_mode != dev_priv->relative_constants_mode) {
+		if (instp_mode != params->ctx->relative_constants_mode) {
 			if (INTEL_INFO(dev)->gen < 4) {
 				DRM_DEBUG("no rel constants on pre-gen4\n");
 				ret = -EINVAL;
@@ -1309,7 +1309,7 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
 	}
 
 	if (ring == &dev_priv->ring[RCS] &&
-			instp_mode != dev_priv->relative_constants_mode) {
+			instp_mode != params->ctx->relative_constants_mode) {
 		ret = intel_ring_begin(params->request, 4);
 		if (ret)
 			goto error;
@@ -1320,7 +1320,7 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
 		intel_ring_emit(ring, instp_mask << 16 | instp_mode);
 		intel_ring_advance(ring);
 
-		dev_priv->relative_constants_mode = instp_mode;
+		params->ctx->relative_constants_mode = instp_mode;
 	}
 
 	if (args->flags & I915_EXEC_GEN7_SOL_RESET) {
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 825fa7a..9ff409d 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -889,7 +889,7 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
 			return -EINVAL;
 		}
 
-		if (instp_mode != dev_priv->relative_constants_mode) {
+		if (instp_mode != params->ctx->relative_constants_mode) {
 			if (instp_mode == I915_EXEC_CONSTANTS_REL_SURFACE) {
 				DRM_DEBUG("rel surface constants mode invalid on gen5+\n");
 				return -EINVAL;
@@ -929,7 +929,7 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
 		return ret;
 
 	if (ring == &dev_priv->ring[RCS] &&
-	    instp_mode != dev_priv->relative_constants_mode) {
+	    instp_mode != params->ctx->relative_constants_mode) {
 		ret = intel_logical_ring_begin(params->request, 4);
 		if (ret)
 			return ret;
@@ -940,7 +940,7 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
 		intel_logical_ring_emit(ringbuf, instp_mask << 16 | instp_mode);
 		intel_logical_ring_advance(ringbuf);
 
-		dev_priv->relative_constants_mode = instp_mode;
+		params->ctx->relative_constants_mode = instp_mode;
 	}
 
 	exec_start = params->batch_obj_vm_offset +
-- 
1.9.1