From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753445AbcBOOmm (ORCPT ); Mon, 15 Feb 2016 09:42:42 -0500 Received: from mga02.intel.com ([134.134.136.20]:55966 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753299AbcBOOmk (ORCPT ); Mon, 15 Feb 2016 09:42:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,450,1449561600"; d="scan'208";a="912755864" Date: Mon, 15 Feb 2016 16:42:35 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Oleksandr Natalenko Cc: Daniel Vetter , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Vetter , Sonika Jindal , Shashank Sharma , Gary Wang Subject: Re: [REGRESSION] i915: No HDMI output with 4.4 Message-ID: <20160215144234.GV23290@intel.com> References: <20160209101136.GR11240@phenom.ffwll.local> <20160211082105.GC11240@phenom.ffwll.local> <4a6e01cc374f7a120b5baab7b41f1951@natalenko.name> <20160211092639.GX23290@intel.com> <20160211140117.GC23290@intel.com> <1059a4b341fb208959a262f8706fae87@natalenko.name> <20160212232329.GS23290@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 15, 2016 at 10:55:33AM +0200, Oleksandr Natalenko wrote: > 13.02.2016 01:23, Ville Syrjälä wrote: > > - Do you have another monitor to try? > > - Do you have another cable to try? > > More on this. > > Computer DVI —— old DVI-HDMI cable —— old monitor HDMI == not working > Computer DVI —— another DVI-HDMI cable —— old monitor HDMI == not > working > Computer DVI —— DVI-DVI cable —— another monitor DVI == works > > So > > > Shouldn't really matter. HDMI and DVI are identical at this level. > > Not quite, as far as I can see. Well, it seems this particular monitor is just somehow funky. It's a bit strange that the hpd interrupt still works. It would seem to indicate that there's two separate voltage thresholds for detection, one for the hpd generation, and another for the live status. I did see something similar on another platforms (CHV) where it had two different hpd detection registers, and those produced different results when the pullup on the hpd pin was misconfigured. Anyway, I'm out of ideas now :( Anyone else got something up their sleeve? I'm starting to think this is going to be our only option: - if (intel_hdmi_set_edid(connector, live_status)) { + if (intel_hdmi_set_edid(connector, true)) { It would more or less turn the live status check into a fixed msleep(80) for the disconnect case. For the connect case it would still break out sooner when live status works. The downside is that if the cable is yanked slowly, we'll still succeed in the ddc communication during unplug and thus fail to notice that the monitor was actually disconnected. But the delay should make that less likely. -- Ville Syrjälä Intel OTC