From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757700Ab1KJPLi (ORCPT ); Thu, 10 Nov 2011 10:11:38 -0500 Received: from mail-wy0-f174.google.com ([74.125.82.174]:53172 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751048Ab1KJPLh (ORCPT ); Thu, 10 Nov 2011 10:11:37 -0500 Message-ID: <4EBBE9A1.8020501@gmail.com> Date: Thu, 10 Nov 2011 16:11:29 +0100 From: Daniel Mack User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 MIME-Version: 1.0 To: dri-devel@lists.freedesktop.org CC: jbarnes@virtuousgeek.org, harald@redhat.com, Keith Packard , linux-kernel@vger.kernel.org Subject: Re: Strange effect with i915 backlight controller References: <4EB3F860.6010408@gmail.com> <4EB87E6A.3060403@gmail.com> In-Reply-To: <4EB87E6A.3060403@gmail.com> X-Enigmail-Version: 1.3.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/08/2011 01:57 AM, Daniel Mack wrote: > Didn't get any response yet, hence copying LKML for a broader audience. Nobody, really? This is a rather annoying regression, as touching the brightness keys appearantly switches off the whole machine. I'm sure this is trivial to fix, I just don't have the insight of this driver and the chipset. Any pointer greatly appreciated, and I can test patches. Thanks, Daniel > > On 11/04/2011 03:36 PM, Daniel Mack wrote: >> I'm facing a bug on a Samsung X20 notebook which features an i915 >> chipset (output of 'lspci -v' attached). >> >> The effect is that setting the backlight to odd values causes the value >> to be misinterpreted. Harald Hoyer (cc:) had the same thing on a Netbook >> (I don't recall which model it was). >> >> So this will turn the backlight to full brightness: >> >> # cat /sys/class/backlight/intel_backlight/max_brightness >> 29750 >> # echo 29750 > /sys/class/backlight/intel_backlight/brightness >> >> However, writing 29749 will turn the display backlight off, and 29748 >> appears to be the next valid lower value. >> >> It seems like the IS_PINEVIEW() branch in >> drivers/gpu/drm/i915/intel_panel.c:intel_panel_actually_set_backlight() >> could do the right thing, but this code is written for an entirely >> different model, right? >> >> I can reproduce this on 3.0 and 3.1 vanilla as well as with the current >> mainline git. >> >> Let me know if there is any patch that I can test. >> >> >> Thanks, >> Daniel >