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-rw-r--r--drivers/usb/host/xhci-ring.c21
1 files changed, 11 insertions, 10 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index b2d654b7477..54139a2f06c 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2684,6 +2684,10 @@ static u32 xhci_v1_0_td_remainder(int running_total, int trb_buff_len,
{
int packets_transferred;
+ /* One TRB with a zero-length data packet. */
+ if (running_total == 0 && trb_buff_len == 0)
+ return 0;
+
/* All the TRB queueing functions don't count the current TRB in
* running_total.
*/
@@ -3125,20 +3129,15 @@ static int count_isoc_trbs_needed(struct xhci_hcd *xhci,
struct urb *urb, int i)
{
int num_trbs = 0;
- u64 addr, td_len, running_total;
+ u64 addr, td_len;
addr = (u64) (urb->transfer_dma + urb->iso_frame_desc[i].offset);
td_len = urb->iso_frame_desc[i].length;
- running_total = TRB_MAX_BUFF_SIZE - (addr & (TRB_MAX_BUFF_SIZE - 1));
- running_total &= TRB_MAX_BUFF_SIZE - 1;
- if (running_total != 0)
- num_trbs++;
-
- while (running_total < td_len) {
+ num_trbs = DIV_ROUND_UP(td_len + (addr & (TRB_MAX_BUFF_SIZE - 1)),
+ TRB_MAX_BUFF_SIZE);
+ if (num_trbs == 0)
num_trbs++;
- running_total += TRB_MAX_BUFF_SIZE;
- }
return num_trbs;
}
@@ -3250,9 +3249,11 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
addr = start_addr + urb->iso_frame_desc[i].offset;
td_len = urb->iso_frame_desc[i].length;
td_remain_len = td_len;
- /* FIXME: Ignoring zero-length packets, can those happen? */
total_packet_count = roundup(td_len,
le16_to_cpu(urb->ep->desc.wMaxPacketSize));
+ /* A zero-length transfer still involves at least one packet. */
+ if (total_packet_count == 0)
+ total_packet_count++;
burst_count = xhci_get_burst_count(xhci, urb->dev, urb,
total_packet_count);
residue = xhci_get_last_burst_packet_count(xhci,