From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757728Ab0CaA2i (ORCPT ); Tue, 30 Mar 2010 20:28:38 -0400 Received: from kroah.org ([198.145.64.141]:48909 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756254Ab0C3XMV (ORCPT ); Tue, 30 Mar 2010 19:12:21 -0400 X-Mailbox-Line: From linux@linux.site Tue Mar 30 15:58:28 2010 Message-Id: <20100330225828.133741053@linux.site> User-Agent: quilt/0.47-14.9 Date: Tue, 30 Mar 2010 15:57:34 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Alan Stern , Greg Kroah-Hartman Subject: [32/89] USB: EHCI: fix handling of unusual interrupt intervals In-Reply-To: <20100330230520.GA28779@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.31-stable review patch. If anyone has any objections, please let us know. ------------------ From: Alan Stern commit 1b9a38bfa6e664ff02511314f5586d711c83cc91 upstream. This patch (as1320) fixes two problems related to interrupt-URB scheduling in ehci-hcd. URBs with an interval of 2 or 4 microframes aren't handled. For the time being, the patch reduces to interval to 1 uframe. URBs are constrained to have an interval no larger than 1024 frames by usb_submit_urb(). But some EHCI controllers allow use of a schedule as short as 256 frames; for these controllers we may have to decrease the interval to the actual schedule length. The second problem isn't very significant since few devices expose interrupt endpoints with an interval larger than 256 frames. But the first problem is critical; it will prevent the kernel from working with devices having interrupt intervals of 2 or 4 uframes. Signed-off-by: Alan Stern Tested-by: Glynn Farrow Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-q.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -802,9 +802,10 @@ qh_make ( * But interval 1 scheduling is simpler, and * includes high bandwidth. */ - dbg ("intr period %d uframes, NYET!", - urb->interval); - goto done; + urb->interval = 1; + } else if (qh->period > ehci->periodic_size) { + qh->period = ehci->periodic_size; + urb->interval = qh->period << 3; } } else { int think_time; @@ -827,6 +828,10 @@ qh_make ( usb_calc_bus_time (urb->dev->speed, is_input, 0, max_packet (maxp))); qh->period = urb->interval; + if (qh->period > ehci->periodic_size) { + qh->period = ehci->periodic_size; + urb->interval = qh->period; + } } }