From: Janusz Krzysztofik janusz.krzysztofik@linux.intel.com
commit a8899b8728013c7b2456f0bfa20e5fea85ee0fd1 upstream.
Commit b97060a99b01 ("drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC") extended the API of intel_gt_retire_requests_timeout() with an extra argument 'remaining_timeout', intended for passing back unconsumed portion of requested timeout when 0 (success) is returned. However, when request retirement happens to succeed despite an error returned by a call to dma_fence_wait_timeout(), that error code (a negative value) is passed back instead of remaining time. If we then pass that negative value forward as requested timeout to intel_uc_wait_for_idle(), an explicit BUG will be triggered.
If request retirement succeeds but an error code is passed back via remaininig_timeout, we may have no clue on how much of the initial timeout might have been left for spending it on waiting for GuC to become idle. OTOH, since all pending requests have been successfully retired, that error code has been already ignored by intel_gt_retire_requests_timeout(), then we shouldn't fail.
Assume no more time has been left on error and pass 0 timeout value to intel_uc_wait_for_idle() to give it a chance to return success if GuC is already idle.
v3: Don't fail on any error passed back via remaining_timeout.
v2: Fix the issue on the caller side, not the provider.
Fixes: b97060a99b01 ("drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC") Signed-off-by: Janusz Krzysztofik janusz.krzysztofik@linux.intel.com Cc: stable@vger.kernel.org # v5.15+ Reviewed-by: Andrzej Hajda andrzej.hajda@intel.com Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20221121145655.75141-2-janusz.... (cherry picked from commit f235dbd5b768e238d365fd05d92de5a32abc1c1f) Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/i915/gt/intel_gt.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/gt/intel_gt.c +++ b/drivers/gpu/drm/i915/gt/intel_gt.c @@ -650,8 +650,13 @@ int intel_gt_wait_for_idle(struct intel_ return -EINTR; }
- return timeout ? timeout : intel_uc_wait_for_idle(>->uc, - remaining_timeout); + if (timeout) + return timeout; + + if (remaining_timeout < 0) + remaining_timeout = 0; + + return intel_uc_wait_for_idle(>->uc, remaining_timeout); }
int intel_gt_init(struct intel_gt *gt)