[PATCH v6 07/25] drm/i915: Mark the current context as lost on suspend

Chris Wilson
2016-04-26T20:06:40Z

In order to force a reload of the context image upon resume, we first
need to mark its absence on suspend. Currently we are failing to restore
the golden context state and any context w/a to the default context
after resume.

One oversight corrected, is that we had forgotten to reapply the L3
remapping when restoring the lost default context.

v2: Remove deprecated WARN.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_gem.c | 1 +
drivers/gpu/drm/i915/i915_gem_context.c | 54 ++++++++++++++-------------------
3 files changed, 25 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 32f05979ade7..c3fbc056d6aa 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3293,6 +3293,7 @@ void i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj);

/* i915_gem_context.c */
int __must_check i915_gem_context_init(struct drm_device *dev);
+void i915_gem_context_lost(struct drm_i915_private *dev_priv);
void i915_gem_context_fini(struct drm_device *dev);
void i915_gem_context_reset(struct drm_device *dev);
int i915_gem_context_open(struct drm_device *dev, struct drm_file *file);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 40f6504de7c1..f9ef11273698 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4711,6 +4711,7 @@ i915_gem_suspend(struct drm_device *dev)
i915_gem_retire_requests(dev);

i915_gem_stop_engines(dev);
+ i915_gem_context_lost(dev_priv);
mutex_unlock(&dev->struct_mutex);

cancel_delayed_work_sync(&dev_priv->gpu_error.hangcheck_work);
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 4e12bae5c659..05752a2f1810 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -90,6 +90,8 @@
#include "i915_drv.h"
#include "i915_trace.h"

+#define ALL_L3_SLICES(dev) (1 << NUM_L3_SLICES(dev)) - 1
+
/* This is a HW constraint. The value below is the largest known requirement
* I've seen in a spec to date, and that was a workaround for a non-shipping
* part. It should be safe to decrease this, but it's more future proof as is.
@@ -249,7 +251,7 @@ __create_hw_context(struct drm_device *dev,
/* NB: Mark all slices as needing a remap so that when the context first
* loads it will restore whatever remap state already exists. If there
* is no remap info, it will be a NOP. */
- ctx->remap_slice = (1 << NUM_L3_SLICES(dev)) - 1;
+ ctx->remap_slice = ALL_L3_SLICES(dev_priv);

ctx->hang_stats.ban_period_seconds = DRM_I915_CTX_BAN_PERIOD;

@@ -336,7 +338,6 @@ static void i915_gem_context_unpin(struct intel_context *ctx,
void i915_gem_context_reset(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
- int i;

if (i915.enable_execlists) {
struct intel_context *ctx;
@@ -345,17 +346,7 @@ void i915_gem_context_reset(struct drm_device *dev)
intel_lr_context_reset(dev_priv, ctx);
}

- for (i = 0; i < I915_NUM_ENGINES; i++) {
- struct intel_engine_cs *engine = &dev_priv->engine[i];
-
- if (engine->last_context) {
- i915_gem_context_unpin(engine->last_context, engine);
- engine->last_context = NULL;
- }
- }
-
- /* Force the GPU state to be reinitialised on enabling */
- dev_priv->kernel_context->legacy_hw_ctx.initialized = false;
+ i915_gem_context_lost(dev_priv);
}

int i915_gem_context_init(struct drm_device *dev)
@@ -403,11 +394,29 @@ int i915_gem_context_init(struct drm_device *dev)
return 0;
}

+void i915_gem_context_lost(struct drm_i915_private *dev_priv)
+{
+ struct intel_engine_cs *engine;
+
+ for_each_engine(engine, dev_priv) {
+ if (engine->last_context == NULL)
+ continue;
+
+ i915_gem_context_unpin(engine->last_context, engine);
+ engine->last_context = NULL;
+ }
+
+ /* Force the GPU state to be reinitialised on enabling */
+ dev_priv->kernel_context->legacy_hw_ctx.initialized = false;
+ dev_priv->kernel_context->remap_slice = ALL_L3_SLICES(dev_priv);
+}
+
void i915_gem_context_fini(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_context *dctx = dev_priv->kernel_context;
- int i;
+
+ i915_gem_context_lost(dev_priv);

if (dctx->legacy_hw_ctx.rcs_state) {
/* The only known way to stop the gpu from accessing the hw context is
@@ -415,26 +424,9 @@ void i915_gem_context_fini(struct drm_device *dev)
* other code, leading to spurious errors. */
intel_gpu_reset(dev, ALL_ENGINES);

- /* 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
- * to default context. So we need to unreference the base object once
- * to offset the do_switch part, so that i915_gem_context_unreference()
- * can then free the base object correctly. */
- WARN_ON(!dev_priv->engine[RCS].last_context);
-
i915_gem_object_ggtt_unpin(dctx->legacy_hw_ctx.rcs_state);
}

- for (i = I915_NUM_ENGINES; --i >= 0;) {
- struct intel_engine_cs *engine = &dev_priv->engine[i];
-
- if (engine->last_context) {
- i915_gem_context_unpin(engine->last_context, engine);
- engine->last_context = NULL;
- }
- }
-
i915_gem_context_unreference(dctx);
dev_priv->kernel_context = NULL;