From patchwork Fri Apr 29 19:47:02 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 742261 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p3TJlKgN018273 for ; Fri, 29 Apr 2011 19:47:42 GMT Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 861869EB3B for ; Fri, 29 Apr 2011 12:47:18 -0700 (PDT) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mx1.suse.de (cantor.suse.de [195.135.220.2]) by gabe.freedesktop.org (Postfix) with ESMTP id DD5BA9E772 for ; Fri, 29 Apr 2011 12:47:08 -0700 (PDT) Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.221.2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.suse.de (Postfix) with ESMTP id 0B2245362F; Fri, 29 Apr 2011 21:47:03 +0200 (CEST) Date: Fri, 29 Apr 2011 21:47:02 +0200 Message-ID: From: Takashi Iwai To: Melchior FRANZ 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") Cc: Linus Torvalds , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+patchwork-dri-devel=patchwork.kernel.org@lists.freedesktop.org Errors-To: dri-devel-bounces+patchwork-dri-devel=patchwork.kernel.org@lists.freedesktop.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Fri, 29 Apr 2011 19:47:42 +0000 (UTC) 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; } }