Subject: [PATCH 1/2] ARM: tegra: add Acer Chromebook 13 device tree

From: [email-masked] (Stephen Warren)
Date: Thu, 15 Jan 2015 10:18:32 -0700

On 01/15/2015 12:50 AM, Thierry Reding wrote:
> On Wed, Jan 14, 2015 at 08:02:25AM +0100, Tomeu Vizoso wrote:
>> On 14 January 2015 at 01:32, Dylan Reid <[email-masked]> wrote:
>>> On Tue, Jan 13, 2015 at 9:49 AM, Tomeu Vizoso <[email-masked]> wrote:
>>>> On 13 August 2014 at 03:56, Dylan Reid <[email-masked]> wrote:
>>>>> The Acer Chromebook 13, codenamed "Big", contains an NVIDIA tegra124
>>>>> processor and is similar to the Venice2 reference platform.
>>>>>
>>>>> The keyboard, USB 2, audio, HDMI, sdcard and emmc have been tested
>>>>> and work on the 1366x768 models.  I haven't tried on the HD systems
>>>>> yet.
>>>>
>>>> Hi Dylan,
>>>>
>>>> do you have any notes on how you tested audio? I have been fiddling a
>>>> bit with amixer but haven't been able to get any sound from the
>>>> speakers nor the headphones.
>>>
>>> I don't have any notes, and it's been a while since I tried it.  To
>>> the best of my knowledge, I loaded the UCM config from the ChromeOS
>>> tree manually with alsaucm, then enabled/disabled headphones from
>>> there.
>>>
>>> https://chromium.googlesource.com/chromiumos/third_party/adhd/+/master/ucm-config/nyan/NVIDIA%20Tegra%20Venice2/
>>>
>>> The important stuff is all in the enable sequence of HiFi.conf
>>>
>>> Let me know if that helps.
>>
>> Thanks, it does work fine now. Will submit that conf file upstream.
>
> Out of curiosity, where is "upstream" for UCM configuration files? It'd
> be interesting to collect files for other Tegra boards there. I find it
> rather tedious figuring out time and time again what control needs to be
> toggled to enable a certain output.
>
> Stephen, since you undoubtedly have the most experience with upstream
> audio, do you happen to know if we have something like that for the
> other upstream-supported boards?

I typically rely on the disto restoring settings from asound.state 
during boot, and saving them from HW during shutdown. I then put that 
asound.state on any filesystems I create.

Adding UCM configurations sounds like it'd be a better alternative, 
presuming there's some automatic way for the distro to correlate the HW 
name to the UCM file name and automatically apply it during boot or 
audio startup.