xhci: Fix mult base in endpoint bandwidth info.

The "Mult" bits in the SuperSpeed Endpoint Companion Descriptor are
zero-based, and the xHCI host controller wants them to be zero-based in
the input context.  However, for the bandwidth math, we want them to be
one-based.  Fix this.

Fix the documentation about the endpoint bandwidth mult variable in the
xhci.h file, which says it is zero-based.  Also fix the documentation
about num_packets, which is also one-based, not zero-based.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 7 insertions, 5 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index c4b8959e01e7..94a8b28d602e 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1473,11 +1473,12 @@ void xhci_update_bw_info(struct xhci_hcd *xhci,
                         /* Added or changed endpoint */
                         bw_info->ep_interval = CTX_TO_EP_INTERVAL(
                                         le32_to_cpu(ep_ctx->ep_info));
-                        bw_info->mult = CTX_TO_EP_MULT(
-                                        le32_to_cpu(ep_ctx->ep_info));
-                        /* Number of packets is zero-based in the input context,
-                         * but we want one-based for the interval table.
+                        /* Number of packets and mult are zero-based in the
+                         * input context, but we want one-based for the
+                         * interval table.
                          */
+                        bw_info->mult = CTX_TO_EP_MULT(
+                                        le32_to_cpu(ep_ctx->ep_info)) + 1;
                         bw_info->num_packets = CTX_TO_MAX_BURST(
                                         le32_to_cpu(ep_ctx->ep_info2)) + 1;
                         bw_info->max_packet_size = MAX_PACKET_DECODED(
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 13f1c23ed19d..752a500f8695 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -747,8 +747,9 @@ struct xhci_stream_info {
  * (DMI) also limits the total bandwidth (across all domains) that can be used.
  */
 struct xhci_bw_info {
+        /* ep_interval is zero-based */
         unsigned int            ep_interval;
-        /* mult and num_packets are zero-based */
+        /* mult and num_packets are one-based */
         unsigned int            mult;
         unsigned int            num_packets;
         unsigned int            max_packet_size;