Re: [PATCH 0/3] Make HDMI ELD usable with hotplug

From: Wang xingchao <xingchao.wang@linux.intel.com>
To: David Henningsson <david.henningsson@canonical.com>,
	Takashi Iwai <tiwai@suse.de>,
	alsa-devel@alsa-project.org, fengguang.wu@intel.com,
	pierre-louis.bossart@linux.intel.com,
	Wang Xingchao <xingchao.wang@intel.com>
Subject: Re: [PATCH 0/3] Make HDMI ELD usable with hotplug
Date: Tue, 19 Feb 2013 10:39:55 +0800	[thread overview]
Message-ID: <20130219023954.GA7400@wxc-intel> (raw)
In-Reply-To: <20130218223942.GB3605@sci.fi>

On Tue, Feb 19, 2013 at 12:39:42AM +0200, Ville Syrjälä 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 <xingchao.wang@intel.com>
> > >      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

Yes i agree it's a common issue should be fixed not only for HSW. In fact
i started to fix the hotplug issue when it's reported from Chromeos, and the
hardware is for Ivybridge/Sandybridge only. Later we find HSW has same problem
and we fix it too.
I donot have Arrandle HW for test/verify, but if it's same issue, i can
continue to fix it.

thanks
--xingchao
> 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.
> 
> -- 
> Ville Syrjälä
> syrjala@sci.fi
> http://www.sci.fi/~syrjala/
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