Hi Chris:
How about this one? :)
diff --git a/drivers/gpu/drm/i915/i915_dma.c
b/drivers/gpu/drm/i915/i915_dma.c
index c5349fa..013039e 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1134,6 +1134,21 @@ int i915_driver_unload(struct drm_device *dev)
i915_global_gtt_cleanup(dev);
+ /*
+ * The only known way to stop the gpu from accessing the hw
context in
+ * graphics memory space is to reset it. Do this as the very last
+ * operation to avoid confusing other code, leading to spurious
errors.
+ *
+ * Besides, we also need to restore HW workload submission mode back
+ * to default mode when shutdown i915.
+ *
+ * It makes i915 module loading/unloading be able to switch between
+ * different workload submission mode on gen8+. And according to
B-spec,
+ * the only way to reset HW workload submission mode to default
mod is GPU reset.
+ */
+ if (INTEL_INFO(dev)->gen >= 5)
+ intel_gpu_reset(dev);
+
intel_uncore_fini(dev);
if (dev_priv->regs != NULL)
pci_iounmap(dev->pdev, dev_priv->regs);
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c
b/drivers/gpu/drm/i915/i915_gem_context.c
index a7e58a8..376ee6b 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -373,11 +373,6 @@ void i915_gem_context_fini(struct drm_device *dev)
int i;
if (dctx->legacy_hw_ctx.rcs_state) {
- /* The only known way to stop the gpu from accessing the
hw context is
- * to reset it. Do this as the very last operation to
avoid confusing
- * other code, leading to spurious errors. */
- intel_gpu_reset(dev);
-
/* When default context is created and switched to,
base object refcount
* will be 2 (+1 from object creation and +1 from
do_switch()).
* i915_gem_context_fini() will be called after
gpu_idle() has switched
于 07/07/15 19:17, Chris Wilson 写道:
On Tue, Jul 07, 2015 at 03:38:37AM +0800, Zhi Wang wrote:
Hi Chris:
Thanks for the comments! I can understand that we're concerned
about regressions, so this is why I think put this reset in module
unload path looks much safer. For safety, maybe we should only reset
GPU perhaps only when GEN >= 6? That looks much easier and safer,
also combine execlist reset and power context reset.
Or we just add this before i915_uncore_fini() inside
i915_driver_unload()? This way looks much safer?
How about this one?
No, if we are just targetting execlists, then disabling it in
cleanup_ringbuffers as before is the cleanest (as that is the opposite
stage to where we enable them).
The reset in i915_driver_unload() is preferred to replace all the resets
required during unload. It is safe to move the context reset here as we
do not disturb the GTT state between unpining the context and here.
Making it conditional on gen>=5 is probably a good first step.
-Chris
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