From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753569Ab1AUEQm (ORCPT ); Thu, 20 Jan 2011 23:16:42 -0500 Received: from mail-wy0-f174.google.com ([74.125.82.174]:59415 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751788Ab1AUEQk (ORCPT ); Thu, 20 Jan 2011 23:16:40 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=amXCGj9V7q0zGQOq3bHiCeR91wRQKPQqE04wWbFiBkZUKUtiDNGlIWpC/D5bgCIZ9L iq1fjIMklwiJ1qdJCFeyJBIXRRnu//wSU/tWm8VPcfoZDktyiuWSKf7XbmW4upvqLSV+ uRlHUJYoFZfnxGe46VlFCH2hhmvpjxvRZSQJg= Subject: Re: regression 2.6.37 -> 2.6.38-rc1: after suspend backlight cannot be adjusted From: Eric Dumazet To: Norbert Preining Cc: linux-kernel@vger.kernel.org, ACPI Devel Mailing List , Linus Torvalds In-Reply-To: <1295583107.2613.45.camel@edumazet-laptop> References: <20110121015529.GD9796@gamma.logic.tuwien.ac.at> <1295583107.2613.45.camel@edumazet-laptop> Content-Type: text/plain; charset="UTF-8" Date: Fri, 21 Jan 2011 05:16:34 +0100 Message-ID: <1295583394.2613.47.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le vendredi 21 janvier 2011 à 05:11 +0100, Eric Dumazet a écrit : > Le vendredi 21 janvier 2011 à 10:55 +0900, Norbert Preining a écrit : > > Hi everyone, > > > > (please Cc) > > > > going to 2.6.38-rc1 I see the following regression: After reboot I > > can easily adjust the backlight with the keys on my keyboard, but > > after a suspend-to-ram this does not work anymore. > > > > This is a Sony laptop, and backlight is controlled by the video > > acpi driver AFAIR. > > > > Hi Norbert > > Maybe this is the problem Linus had to bisect, you could try his patch : > > http://marc.info/?l=linux-netdev&m=129556877919576&w=2 > > Thanks ! > Or just pull linux-2.6, since patch is now committed commit 28e58ee8ce1f0e69c207f747b7b9054b071e328d Author: Linus Torvalds Date: Thu Jan 20 16:21:59 2011 -0800 Fix broken "pipe: use event aware wakeups" optimization Commit e462c448fdc8 ("pipe: use event aware wakeups") optimized the pipe event wakeup calls to avoid wakeups if the events do not match the requested set. However, the optimization was buggy, in that it didn't actually use the correct sets for the events: when we make room for more data to be written, the pipe poll() routine will return both the POLLOUT _and_ POLLWRNORM bits. Similarly for read. And most critically, when a pipe is released, that will potentially result in POLLHUP|POLLERR (depending on whether it was the last reader or writer), not just the regular POLLIN|POLLOUT. This bug showed itself as a hung gnome-screensaver-dialog process, stuck forever (or at least until it was poked by a signal or by being traced) in a poll() system call. Cc: Davide Libenzi Cc: David S. Miller Cc: Eric Dumazet Cc: Jens Axboe Cc: Andrew Morton Signed-off-by: Linus Torvalds