From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [PATCH] drm/i915: Reject modeset when the same digital port is used more than once Date: Mon, 19 May 2014 17:45:07 +0300 Message-ID: <20140519144506.GC27580@intel.com> References: <1400509149-25640-1-git-send-email-ville.syrjala@linux.intel.com> <20140519142957.GO8790@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTP id DFB606E747 for ; Mon, 19 May 2014 07:45:17 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20140519142957.GO8790@phenom.ffwll.local> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Mon, May 19, 2014 at 04:29:57PM +0200, Daniel Vetter wrote: > On Mon, May 19, 2014 at 05:19:09PM +0300, ville.syrjala@linux.intel.com w= rote: > > From: Ville Syrj=E4l=E4 > > = > > On pre-HSW we have two encoders per digital port: one HDMI, one DP. > > However they are the same physical port in hardware and we can't enable > > both at the same time. Reject the modeset if the user attempts this. > > = > > So far we've been saved by the fact that we never see both HDMI and DP > > connectors as connected. But if the user decides to force a mode anyway, > > all kinds of funny stuff might happen. > > = > > Unfortunately we don't seem to have any way to inform userspace that > > such configurations are invalid except by returning an error from > > setcrtc. possible_clones only covers real cloning situations, and > > looking at the connector names doesn't work either since we don't > > always register both connectors for the same port. I suppose the > > only way to fix that would be to expose only a single encoder per > > digital port like we do on HSW+ but that would be a fairly large > > undertaking for little gain. > > = > > kms_setmode hits this since it forces modes on non-connected VGA and > > HDMI connectors. Previosuly it just resulted in weirdness such as > > failed link training. With this patch it will now get an error back > > from the kernel and will die with an assert since it thinks that the > > configuration should be fine. > > = > > Signed-off-by: Ville Syrj=E4l=E4 > = > Do we have a bugzilla for this somewhere? No idea. Can't spot anything right now that would match my IVB kms_setmode symptoms (tons of link training failures when the same port gets used for both DP and HDMI). -- = Ville Syrj=E4l=E4 Intel OTC