On Tue, Jul 27, 2021 at 06:01:18PM -0700, Belgaumkar, Vinay wrote:
On 7/27/2021 5:20 PM, Matthew Brost wrote:
On Mon, Jul 26, 2021 at 12:07:52PM -0700, Vinay Belgaumkar wrote:
The assumption when it was added was there would be no wakerefs held. However, if we fail to enable SLPC, we will still be holding a wakeref.
So this is if intel_guc_slpc_enable() fails, right? Not seeing where the wakeref is taken. It also seems wrong not to drop the wakeref before calling intel_guc_submission_disable, hence the GEM_BUG_ON in this function.
Can you explain this bit more?
I should change the desc a little. The BUG_ON assumed GT would not be awake i.e at shutdown, and there would be 0 GT_PM references. However, this slpc_enable is in gt_resume path (gt_init_hw calls uc_init_hw). Here, gt_pm_get reference is held, so it will result in BUG_ON when submission_disable is called.
Ok, I see the code path. With a better commit message: Reviewed-by: Matthew Brost matthew.brost@intel.com
Thanks, Vinay.
Matt
Signed-off-by: Vinay Belgaumkar vinay.belgaumkar@intel.com
drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index b6338742a594..48cbd800ca54 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -2523,10 +2523,6 @@ void intel_guc_submission_enable(struct intel_guc *guc) void intel_guc_submission_disable(struct intel_guc *guc) {
- struct intel_gt *gt = guc_to_gt(guc);
- GEM_BUG_ON(gt->awake); /* GT should be parked first */
- /* Note: By the time we're here, GuC may have already been reset */ }
-- 2.25.0