From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Henningsson Subject: Re: [PATCH 0/3] Make HDMI ELD usable with hotplug Date: Tue, 19 Feb 2013 06:55:36 +0100 Message-ID: <512313D8.901@canonical.com> References: <1361193073-7199-1-git-send-email-david.henningsson@canonical.com> <512231B9.6000408@canonical.com> <20130218223942.GB3605@sci.fi> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1"; Format="flowed" Content-Transfer-Encoding: quoted-printable Return-path: Received: from youngberry.canonical.com (youngberry.canonical.com [91.189.89.112]) by alsa0.perex.cz (Postfix) with ESMTP id B965926519E for ; Tue, 19 Feb 2013 06:55:34 +0100 (CET) In-Reply-To: <20130218223942.GB3605@sci.fi> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Takashi Iwai , alsa-devel@alsa-project.org, fengguang.wu@intel.com, pierre-louis.bossart@linux.intel.com, Wang Xingchao List-Id: alsa-devel@alsa-project.org On 02/18/2013 11:39 PM, Ville Syrj=E4l=E4 wrote: > On Mon, Feb 18, 2013 at 02:50:49PM +0100, David Henningsson wrote: >> On 02/18/2013 02:35 PM, Takashi Iwai wrote: >>> At Mon, 18 Feb 2013 14:11:10 +0100, >>> David Henningsson wrote: >>>> >>>> I'm experimenting with using ELD information in PulseAudio and found >>>> that it didn't work very well with hotplugging. >>>> Neither the proc file nor the ELD kcontrol was cleared correctly after >>>> unplug, and there was no way (except polling) to find out when ELD >>>> has become available. >>> >>> Did you try Xingchao's patch for drm/i915? It's queued in >>> drm-intel-next: >>> >>> commit 7b9f35a6dd72f89452c58bbdbaf063027bf857ec >>> Author: Wang Xingchao >>> Date: Tue Jan 22 23:25:25 2013 +0800 >>> >>> drm/i915: HDMI/DP - ELD info refresh support for Haswell >> >> Thanks for the hint. I'm currently developing not on a Haswell machine, >> but an (I think) Arrandale that I bought a few years ago. So I guess >> this patch does not have any effect on my hw? > > While reviewing that patch I asked whether we need something like that > on other platforms. Unfortunately I didn't get a real answer. The logic > in the patch would seem to apply equally to all platforms, not just HSW. > We also seem to be doing silly things like flipping the ELD valid bit > in the register on and off a few times when we update the ELD. But I'm > not all that familiar with the topic so take my ramblings with a pinch > of salt. > > But in any case, if you're seeing a problem with the behaviour of i915 > you should definitely report it. Looking at the HDA spec [1], e g "Figure 72: PD and ELDV unsolicited = responses flow for digital display codecs" it looks like it's not valid = to first send the PD bit and then ELDV a while later. So then I guess = it's an issue that this actually seem to happen on the machine I use for = testing this code. From the same figure, it also looks like ELDV can be flipped back and = forth (due to mode changes) when PD is true; so making patches that deal = with PD and ELDV independently seem to be the right thing nonetheless. -- = David Henningsson, Canonical Ltd. https://launchpad.net/~diwic [1] = http://www.intel.com/content/www/us/en/standards/high-definition-audio-spec= ification.html