From: Ben Widawsky <benjamin.widawsky@xxxxxxxxx>
This patch just breaks out the logic of context switch skip.
It also adds pd load pre, and pd load post logic (for GEN8).
v2: Use new functions to replace the logic right away (Daniel)
v3: Add missing pd load logic.
Cc: Daniel Vetter <daniel@xxxxxxxx>
Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx>
Signed-off-by: Michel Thierry <michel.thierry@xxxxxxxxx> (v2+)
---
drivers/gpu/drm/i915/i915_gem_context.c | 48 +++++++++++++++++++++++++++++++--
1 file changed, 46 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 70346b0..8474e2c 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -569,6 +569,33 @@ mi_set_context(struct intel_engine_cs *ring,
return ret;
}
+static inline bool should_skip_switch(struct intel_engine_cs *ring,
+ struct intel_context *from,
+ struct intel_context *to)
+{
+ if (from == to && !to->remap_slice)
+ return true;
+
+ return false;
+}
+
+static bool
+needs_pd_load_pre(struct intel_engine_cs *ring, struct intel_context *to)
+{
+ struct drm_i915_private *dev_priv = ring->dev->dev_private;
+
+ return ((INTEL_INFO(ring->dev)->gen < 8) ||
+ (ring != &dev_priv->ring[RCS])) && to->ppgtt;
+}
+
+static bool
+needs_pd_load_post(struct intel_engine_cs *ring, struct intel_context *to)
+{
+ return (!to->legacy_hw_ctx.initialized ||
+ i915_gem_context_is_default(to)) &&
+ to->ppgtt && IS_GEN8(ring->dev);
+}
+
static int do_switch(struct intel_engine_cs *ring,
struct intel_context *to)
{
@@ -584,7 +611,7 @@ static int do_switch(struct intel_engine_cs *ring,
BUG_ON(!i915_gem_obj_is_pinned(from->legacy_hw_ctx.rcs_state));
}
- if (from == to && !to->remap_slice)
+ if (should_skip_switch(ring, from, to))
return 0;
/* Trying to pin first makes error handling easier. */
@@ -602,7 +629,11 @@ static int do_switch(struct intel_engine_cs *ring,
*/
from = ring->last_context;
- if (to->ppgtt) {
+ if (needs_pd_load_pre(ring, to)) {
+ /* Older GENs and non render rings still want the load first,
+ * "PP_DCLV followed by PP_DIR_BASE register through Load
+ * Register Immediate commands in Ring Buffer before submitting
+ * a context."*/
trace_switch_mm(ring, to);
ret = to->ppgtt->switch_mm(to->ppgtt, ring);
if (ret)
@@ -644,6 +675,19 @@ static int do_switch(struct intel_engine_cs *ring,
if (ret)
goto unpin_out;
+ if (needs_pd_load_post(ring, to)) {
+ ret = to->ppgtt->switch_mm(to->ppgtt, ring);
+ /* The hardware context switch is emitted, but we haven't
+ * actually changed the state - so it's probably safe to bail
+ * here. Still, let the user know something dangerous has
+ * happened.
+ */
+ if (ret) {
+ DRM_ERROR("Failed to change address space on context switch\n");
+ goto unpin_out;
+ }
+ }
+
for (i = 0; i < MAX_L3_SLICES; i++) {
if (!(to->remap_slice & (1<<i)))
continue;
--
2.1.1
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