Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755285Ab2JPQym (ORCPT ); Tue, 16 Oct 2012 12:54:42 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:49069 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754974Ab2JPQyk (ORCPT ); Tue, 16 Oct 2012 12:54:40 -0400 Date: Tue, 16 Oct 2012 09:54:36 -0700 From: Greg Kroah-Hartman To: Michael Spang , linux-usb@vger.kernel.org Cc: Dave Jones , Michael Spang , Sarah Sharp , Linux Kernel , greno@verizon.net, Fedora Kernel Team Subject: Re: USB keyboard backlight powering down. Message-ID: <20121016165436.GA5140@kroah.com> References: <20121016152023.GA25506@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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: 1623 Lines: 43 On Tue, Oct 16, 2012 at 12:45:56PM -0400, Michael Spang wrote: > On Tue, Oct 16, 2012 at 11:20 AM, Dave Jones wrote: > > 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 > > I don't think this is related to your problem, as this patch is in > suspend/resume code. It just allows the controller more time to halt. Yeah, that looks odd. But, (adding linux-usb@vger), I think we enabled some "put the device to sleep if it is idle" logic for all devices, which is what is looking like is happening here. The keyboard is being told to go to sleep in order to save power. We are saving more power, but it looks like the user wants to disable it, which makes sense for this device. So, do we do this from within the kernel with a blacklist, or rely on the user knowing how to poke the proper sysfs file to turn the keyboard back on? greg k-h > > Thanks, > Michael -- 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/