From: Corbin McElhanney <corbin.mcelhanney@xxxxxxx>
This comment explains a previous change that adds some complexity
to the context free in dc:
commit 9ad58779a895 ("drm/amd/display: Fix accessing freed memory")
Signed-off-by: Corbin McElhanney <corbin.mcelhanney at amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng at amd.com>
Acked-by: Harry Wentland <Harry.Wentland at amd.com>
---
drivers/gpu/drm/amd/display/dc/core/dc.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 477024c467e6..33c3d88b1c86 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -1740,6 +1740,15 @@ void dc_update_planes_and_stream(struct dc *dc,
}
if (core_dc->current_context != context) {
+
+ /* Since memory free requires elevated IRQL, an interrupt
+ * request is generated by mem free. If this happens
+ * between freeing and reassigning the context, our vsync
+ * interrupt will call into dc and cause a memory
+ * corruption BSOD. Hence, we first reassign the context,
+ * then free the old context.
+ */
+
struct validate_context *old = core_dc->current_context;
core_dc->current_context = context;
--
2.11.0
