From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932067Ab3BQXLY (ORCPT ); Sun, 17 Feb 2013 18:11:24 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45592 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754535Ab3BQWy6 (ORCPT ); Sun, 17 Feb 2013 17:54:58 -0500 Message-Id: <20130217225003.083385422@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 17 Feb 2013 22:50:13 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, Alan Stern , Greg Kroah-Hartman Subject: [ 12/66] USB: EHCI: fix bug in scheduling periodic split transfers In-Reply-To: <20130217225001.621306883@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:a11:96ff:fec6:70c4 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit 3e619d04159be54b3daa0b7036b0ce9e067f4b5d upstream. This patch (as1654) fixes a very old bug in ehci-hcd, connected with scheduling of periodic split transfers. The calculations for full/low-speed bus usage are all carried out after the correction for bit-stuffing has been applied, but the values in the max_tt_usecs array assume it hasn't been. The array should allow for allocation of up to 90% of the bus capacity, which is 900 us, not 780 us. The symptom caused by this bug is that any isochronous transfer to a full-speed device with a maxpacket size larger than about 980 bytes is always rejected with a -ENOSPC error. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/usb/host/ehci-sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index 2b6917d..b476daf 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -213,7 +213,7 @@ static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __hc32 mask) } static const unsigned char -max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 }; +max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 125, 25 }; /* carryover low/fullspeed bandwidth that crosses uframe boundries */ static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])