Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760928Ab1D2TrH (ORCPT ); Fri, 29 Apr 2011 15:47:07 -0400 Received: from cantor.suse.de ([195.135.220.2]:56082 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760906Ab1D2TrE (ORCPT ); Fri, 29 Apr 2011 15:47:04 -0400 Date: Fri, 29 Apr 2011 21:47:02 +0200 Message-ID: From: Takashi Iwai To: Melchior FRANZ Cc: Linus Torvalds , linux-kernel@vger.kernel.org, Chris Wilson , dri-devel@lists.freedesktop.org Subject: Re: i915/kms/backlight-combo mode problem (was: Re: Linux 2.6.39-rc5) In-Reply-To: <201104291941.53663@rk-nord.at> References: <201104291758.06975@rk-nord.at> <201104291941.53663@rk-nord.at> User-Agent: Wanderlust/2.15.6 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.7 Emacs/23.2 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1347 Lines: 42 At Fri, 29 Apr 2011 19:41:53 +0200, Melchior FRANZ wrote: > > * Takashi Iwai -- Friday 29 April 2011: > > Melchior FRANZ wrote: > > > The bug was introduced with commit ba3820ade317ee36e496b9b40d2ec3987dd4aef0 > > > [...] when using KMS my notebook's[2] screen remains dark, because the > > > backlight isn't turned on. > > > Could you check whether the patch below changes the behavior? > > If this cures, it means that the backlight-combo mode doesn't work on > > your machine. > > Yes, that works. (Test was with fafc9929c668f8bae6dd1f109f33a86d2cb3c460, > which is current HEAD.) Looking at bugzilla, the problem seems like the case lbpc=0. What about the patch below instead? Takashi --- diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index a06ff07..ba60218 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -207,7 +207,8 @@ u32 intel_panel_get_backlight(struct drm_device *dev) val &= ~1; pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc); - val *= lbpc; + if (lbpc) + val *= lbpc; } } -- 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/