Browse Source

USB: EHCI: No SSPLIT allowed in uframe 7

The scheduling code in ehci-hcd contains an error.  For full-speed
isochronous-OUT transfers, the EHCI spec forbids scheduling
Start-Split transactions in H-microframe 7, but the driver allows it
anyway.  This patch adds a check to prevent it.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alan Stern 11 years ago
parent
commit
8c05dc598e
1 changed files with 4 additions and 0 deletions
  1. 4 0
      drivers/usb/host/ehci-sched.c

+ 4 - 0
drivers/usb/host/ehci-sched.c

@@ -1286,6 +1286,10 @@ sitd_slot_ok (
 
 	mask = stream->raw_mask << (uframe & 7);
 
+	/* for OUT, don't wrap SSPLIT into H-microframe 7 */
+	if (((stream->raw_mask & 0xff) << (uframe & 7)) >= (1 << 7))
+		return 0;
+
 	/* for IN, don't wrap CSPLIT into the next frame */
 	if (mask & ~0xffff)
 		return 0;