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path: root/drivers/usb/host/xhci-ring.c
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Diffstat (limited to 'drivers/usb/host/xhci-ring.c')
-rw-r--r--drivers/usb/host/xhci-ring.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9673354d70..2647245d5b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -326,7 +326,13 @@ static unsigned int xhci_ring_expansion_needed(struct xhci_hcd *xhci, struct xhc
/* how many trbs will be queued past the enqueue segment? */
trbs_past_seg = enq_used + num_trbs - (TRBS_PER_SEGMENT - 1);
- if (trbs_past_seg <= 0)
+ /*
+ * Consider expanding the ring already if num_trbs fills the current
+ * segment (i.e. trbs_past_seg == 0), not only when num_trbs goes into
+ * the next segment. Avoids confusing full ring with special empty ring
+ * case below
+ */
+ if (trbs_past_seg < 0)
return 0;
/* Empty ring special case, enqueue stuck on link trb while dequeue advanced */