Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755009Ab2JPPUj (ORCPT ); Tue, 16 Oct 2012 11:20:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46034 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754803Ab2JPPUh (ORCPT ); Tue, 16 Oct 2012 11:20:37 -0400 Date: Tue, 16 Oct 2012 11:20:23 -0400 From: Dave Jones To: Michael Spang Cc: Sarah Sharp , Greg Kroah-Hartman , Linux Kernel , greno@verizon.net, Fedora Kernel Team Subject: USB keyboard backlight powering down. Message-ID: <20121016152023.GA25506@redhat.com> Mail-Followup-To: Dave Jones , Michael Spang , Sarah Sharp , Greg Kroah-Hartman , Linux Kernel , greno@verizon.net, Fedora Kernel Team MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1680 Lines: 42 Gerry (CC'd) reported a bug to us that since 3.6.1, his illuminated Logitech USB keyboard doesn't light up until he hits a key, and then it immediately powers back off, defeating the purpose of having an illumated keyboard. Looking over the 3.6.1 changelog, I see this change, which sounds like it might be responsible ? commit ee537508bdc0c00b96ac497f3d82a68f820e6182 Author: Michael Spang Date: Fri Sep 14 13:05:49 2012 -0400 Increase XHCI suspend timeout to 16ms commit a6e097dfdfd189b6929af6efa1d289af61858386 upstream. The Intel XHCI specification says that after clearing the run/stop bit the controller may take up to 16ms to halt. We've seen a device take 14ms, which with the current timeout of 10ms causes the kernel to abort the suspend. Increasing the timeout to the recommended value fixes the problem. This patch should be backported to kernels as old as 2.6.37, that contain the commit 5535b1d5f8885695c6ded783c692e3c0d0eda8ca "USB: xHCI: PCI power management implementation". Signed-off-by: Michael Spang Signed-off-by: Sarah Sharp Signed-off-by: Greg Kroah-Hartman Any thoughts on how we could prevent this generically, or is this something we're going to have to quirk around for specific devices we don't want to power down ? Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/