Re: [PATCH] ALSA: hda/realtek: Add quirk for Lenovo Ideapad S740

[Jaroslav Kysela <perex@perex.cz>]

Dne 16. 04. 21 v 18:25 Takashi Iwai napsal(a):
> On Fri, 16 Apr 2021 18:05:17 +0200,
> Pierre-Louis Bossart wrote:
>>
>>
>>
>> On 4/16/21 3:47 AM, Jaroslav Kysela wrote:
>>> Dne 16. 04. 21 v 10:12 Takashi Iwai napsal(a):
>>>> Lenovo Ideapad S740 requires quite a few COEF setups to make its
>>>> speakers working.  The verb table was provided from Ryan Prescott as
>>>> the result of investigation via qemu:
>>>>    https://github.com/ryanprescott/realtek-verb-tools/wiki/How-to-sniff-verbs-from-a-Windows-sound-driver
>>>
>>> [Cc: to Kailang / Realtek]
>>>
>>> I believe that this sequence contains I2C writes to amplifier chips. It would
>>> be really helpful, if Realtek can provide more information for the I2C master
>>> interface for their codecs (describe basic I2C I/O).
>>
>> The biggest problem is to figure what address/value pairs to write
>> with I2C into the amplifiers, and here the catch is that those I2C/I2S
>> amplifiers may or may not be sourced from Realtek, and it'd be
>> difficult for Realtek to provide documentation on their competition,
>> wouldn't it?
> 
> Sure, that's another problem.  But currently it's not clear even how
> to communicate via I2C/whatever to the underlying chip, as it's done
> via the vendor-specific COEF verb.  At least this could be opened, I
> hope.

The nice thing if we know the I2C master communication is that we can create
I2C bus in the HDA driver and do run i2cdetect to detect the connected chips.
Yes, it's partial information, but it's far more better than this unreadable
coef implementation.

						Jaroslav

-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.