Re: Intel SST on a Bay Trail tablet

[Jarkko Nikula <jarkko.nikula@linux.intel.com>]

Hi

On 03/03/2015 04:16 PM, Antonio Ospite wrote:
> On Mon, 23 Feb 2015 18:39:13 +0100
> Antonio Ospite <ao2@ao2.it> wrote:
>
>> Hi,
>>
>> I am trying to get the Intel SST driver working on a Teclast X98 Air 3G
>> [1], it's a Bay Trail tablet. The tests below have been made with
>> 4.0.0-rc1 and the firmware files from
>> https://git.kernel.org/cgit/linux/kernel/git/firmware/linux-firmware.git/tree/intel
>>
>
> Hi, has anyone had a chance to take a look at my previous message?
>
I forgot to answer... Some earlier notes including Teclast X98 Air 3G 
and patch attempts are collected here:

https://bugzilla.kernel.org/show_bug.cgi?id=86581

Unfortunately bug is not solved since it looks these newer Baytrail 
Windows 8.1 based machines use different SSP port than previous ones and 
Linux DSP firmware is hardcoded for SSP2.

What's interesting does that Android FW use other than SSP2 or does 
Teclast have some extra amplifier.

> [...]
>> Last question, what is the difference between having the device detected
>> by sound/soc/intel/sst-acpi.c (like in my case) opposed to
>> sound/soc/intel/sst/sst_acpi.c? I can see the 80860F28 id in both the
>> files but they seem to load different firmwares.
>>

Different firmware, driver stack and machine driver despite the same LPE 
ACPI ID and codec ACPI ID. (We really should have some additional DMI 
quirks that does the selection because of the same ACPI IDs).

>
> Another thing I noticed is that the Android driver for the rt5640 codec
> defines some controls which are not in the mainline driver:
>
>    OUT MIXR BST3 Switch
>    OUT MIXL BST3 Switch
>    RECMIXR BST3 Switch
>    RECMIXL BST3 Switch
>    IN1 Mode Control
>    IN2 Mode Control
>
I'm not sure but these might be FW implemented DSP controls? Vinod, do 
you know?

-- 
Jarkko