[alsa-devel] [Intel-gfx] [PATCH 0/4] i915 to call hda driver on HDMI plug/unplug

[David Henningsson]

On 2015-07-21 19:37, R, Durgadoss wrote:
> Hi David,
>
>> -----Original Message-----
>> From: Intel-gfx [mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf Of David Henningsson
>> Sent: Tuesday, July 21, 2015 1:27 PM
>> To: alsa-devel at alsa-project.org; intel-gfx at lists.freedesktop.org; tiwai at suse.de; Vetter, Daniel;
>> jani.nikula at 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..?

When running this code with drm.debug=0xe, I can see a lot of calls to 
set different power wells on and off, to the extent that I don't keep 
track of them.

So I assume that means that the i915 driver goes into D3 as well during 
my tests.

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic