Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758536AbZJMAR0 (ORCPT ); Mon, 12 Oct 2009 20:17:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757329AbZJMARZ (ORCPT ); Mon, 12 Oct 2009 20:17:25 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:49324 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756626AbZJMARY (ORCPT ); Mon, 12 Oct 2009 20:17:24 -0400 Date: Mon, 12 Oct 2009 17:16:29 -0700 (PDT) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Nix cc: "Justin P. Mattock" , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Boyan , Dmitry Torokhov , Ed Tomlinson , =?ISO-8859-15?Q?Fr=E9d=E9ric_L=2E_W=2E_Meunier?= , OGAWA Hirofumi Subject: Re: [Bug #14388] keyboard under X with 2.6.31 In-Reply-To: <87ljjgfcbu.fsf@spindle.srvr.nix> Message-ID: References: <56acieJJ2fF.A.nEB.Hzl0KB@chimera> <87ljjgfcbu.fsf@spindle.srvr.nix> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2503 Lines: 54 On Mon, 12 Oct 2009, Nix wrote: > On 12 Oct 2009, Justin P. Mattock uttered the following: > > > Not sure where this stands. Right now all three machines I have seem to be having no issues with the kayboard > > (xserver 1.6.*) I can go and build the latest xserver(1.7) to see if I hit something. > [...] > >> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=14388 > >> Subject : keyboard under X with 2.6.31 > >> Submitter : Fr?d?ric L. W. Meunier > >> Date : 2009-10-07 20:19 (5 days old) > >> First-Bad-Commit: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e043e42bdb66885b3ac10d27a01ccb9972e2b0a3 > >> References : http://marc.info/?l=linux-kernel&m=125494753228217&w=4 > > I have been seeing problems precisely like those described (sometimes > the keyboard dies, sometimes it gets 'stuck' with a key held down, until > I switch TTYs, which generally means killing X as I'm not aware of an > easy way to switch VTs using only the mouse), since I moved to 2.6.31 The particular commit that was bisected to should really not matter for X, except perhaps from a timing standpoint. The problem it fixed was in pty's, and X doesn't use them much if at all (various X _programs_ may, of course, but the symptoms don't sound like it's just a particular X app that has issues, but more of a generic X keyboard handling thing) But for non-pty's, there should be no semantic changes from that commit outside of some general tty timing differences by doing that tty_flush_to_ldisc() at new points. I could fairly easily imagine that some timing difference does expose another longer-standing problem in either the kernel or X itself. So the bisection isn't necessarily wrong, it's just not likely telling us what the real problem is. Of course, maybe there is some race condition in the tty_buffer.c code. We _used_ to not call flush_to_ldisc() except through the workqueue code, so races would not be seen in normal circumstances. Now that flush_to_ldisc() could easily get called both synchronously from tty_read()/tty_poll(), while also being hit from the workqueues. Alan, Ogawa-san, do either of you see some problem in tty_buffer.c, perhaps? Linus -- 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/