diff options
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_guc_submission.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c index 07289a4b5bfa..0b61bf18c3f4 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -475,9 +475,12 @@ static void guc_ring_doorbell(struct i915_guc_client *client) /* pointer of current doorbell cacheline */ db = __get_doorbell(client); - /* we're not expecting the doorbell cookie to change behind our back */ + /* + * We're not expecting the doorbell cookie to change behind our back, + * we also need to treat 0 as a reserved value. + */ cookie = READ_ONCE(db->cookie); - WARN_ON_ONCE(xchg(&db->cookie, cookie + 1) != cookie); + WARN_ON_ONCE(xchg(&db->cookie, cookie + 1 ?: cookie + 2) != cookie); /* XXX: doorbell was lost and need to acquire it again */ GEM_BUG_ON(db->db_status != GUC_DOORBELL_ENABLED); |