drm/i915/gt: Discard stale context state from across idling

Before we idle, on parking, we switch to the kernel context such that we
have a scratch context loaded while the GPU idle, protecting any
precious user state. Be paranoid and assume that the idle state may have
been trashed, and reset the kernel_context image after idling.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200102131707.1463945-4-chris@chris-wilson.co.uk

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/mock_engine.c b/drivers/gpu/drm/i915/gt/mock_engine.c
index 4e1eafa94be9..d0e68ce9aa51 100644
--- a/drivers/gpu/drm/i915/gt/mock_engine.c
+++ b/drivers/gpu/drm/i915/gt/mock_engine.c
@@ -152,6 +152,10 @@ static int mock_context_pin(struct intel_context *ce)
 	return intel_context_active_acquire(ce);
 }
 
+static void mock_context_reset(struct intel_context *ce)
+{
+}
+
 static const struct intel_context_ops mock_context_ops = {
 	.alloc = mock_context_alloc,
 
@@ -161,6 +165,7 @@ static const struct intel_context_ops mock_context_ops = {
 	.enter = intel_context_enter_engine,
 	.exit = intel_context_exit_engine,
 
+	.reset = mock_context_reset,
 	.destroy = mock_context_destroy,
 };