Re: [PATCH 0/4] i915 to call hda driver on HDMI plug/unplug

From: Takashi Iwai <tiwai@suse.de>
To: "R, Durgadoss" <durgadoss.r@intel.com>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	"Koul, Vinod" <vinod.koul@intel.com>,
	"intel-gfx@lists.freedesktop.org"
	<intel-gfx@lists.freedesktop.org>,
	"Vetter, Daniel" <daniel.vetter@intel.com>,
	David Henningsson <david.henningsson@canonical.com>
Subject: Re: [PATCH 0/4] i915 to call hda driver on HDMI plug/unplug
Date: Wed, 22 Jul 2015 10:50:33 +0200	[thread overview]
Message-ID: <s5hzj2oh8yu.wl-tiwai@suse.de> (raw)
In-Reply-To: <4D68720C2E767A4AA6A8796D42C8EB59091CA987@BGSMSX101.gar.corp.intel.com>

On Tue, 21 Jul 2015 19:37:17 +0200,
R, Durgadoss wrote:
> 
> Hi David,
> 
> >-----Original Message-----
> >From: Intel-gfx [mailto:intel-gfx-bounces@lists.freedesktop.org] On Behalf Of David Henningsson
> >Sent: Tuesday, July 21, 2015 1:27 PM
> >To: alsa-devel@alsa-project.org; intel-gfx@lists.freedesktop.org; tiwai@suse.de; Vetter, Daniel;
> >jani.nikula@linux.intel.com
> >Cc: Koul, Vinod; David Henningsson
> >Subject: [Intel-gfx] [PATCH 0/4] i915 to call hda driver on HDMI plug/unplug
> >
> >This patch set aims to resolve three problems:
> >
> > * The first - and most serious one - is that the audio driver is not woken up
> >   properly when in power save modes, especially not when the HDA controller is
> >   in D3. By having the i915 driver call directly into the hda driver, the HDA
> >   driver is always notified that an HDMI hotplug event has happened.
> >
> > * Second, there is currently no way for userspace to match an HDMI audio output
> >   with an HDMI video output. We fix this by sending connector_type and
> >   connector_type_id in the HDMI hotplug callback.
> >
> > * Third, writing ELD info to the hardware just so the HDA driver can read it
> >   from the hardware seems a bit inefficient. We could just pass that information
> >   in the callback, too.
> >
> >The patch in its current form fixes the first of these problems and provides most
> >of the infrastructure for the second and third problem.
> >
> >The patch set is based on 4.2rc2 + my recent codec wakeup patch. So far, it has
> >been tested (and working) on one Skylake machine.
> 
> I believe you tested these patches with hda driver after few cycles of D3.
> By any chance, did you also try this once after i915 driver's D3 cycle also ?
> In this case, can the check_presence_and_report() function get the
> pin presence and ELD valid bits read out properly..?

The code path will call power well on, thus the i915 driver will be
woken up, in anyway.

thanks,

Takashi
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