[Letux-kernel] LetuxOS: Kernel: m-rc 5.3-rc1 successful

[H. Nikolaus Schaller]

> Am 30.07.2019 um 19:38 schrieb Michael Mrozek <EvilDragon at openpandora.org>:
> 
> Am Dienstag, den 30.07.2019, 17:45 +0200 schrieb H. Nikolaus Schaller:
> 
> I think the AESS is the hardware codec part of ABE, that's why it needs
> the firmware running.

Yes. It is a similar thing as the DSP inside of some OMAP3 variants.

> could be wrong though.

IMHO it is right :)

> 
>>> Am 30.07.2019 um 17:41 schrieb H. Nikolaus Schaller <
>>> hns at goldelico.com>:
>>> 
>>> Some additional thoughts:
>>> 
>>> * here is the "Issue" record: 
>>> http://projects.goldelico.com/p/gta04-kernel/issues/883/
>>> 
>>> * the letux/pyra-minimal branch is without any AESS patch (on top
>>> of 5.3-rc2).
>>> I tried audio yesterday on the Pyra but did not get more than
>>> scratchy noise :(
>>> 
>>> * There was a really good description on omappedia but I think it
>>> has gone.
>> 
>> I think I have found it: 
>> http://omappedia.org/wiki/Audio_Drive_Arch#Audio_Back_End_.28ABE.29
>> 
>> "AESS" is also called "ABE" in other contexts. Somehow confusing.
>> 
>> ABE = Audio Back End (= inside OMAP4/5) - Audio Front End = twl6040 +
>> speakers or other sound sources
>> AESS = Audio Engine Sub-system (is part of ABE).
>> 
>>> * I think the Droid 4 is omap4430 + twl6040 + telephony modem and
>>> therefore the
>>> developers may also be interested in this.
>>> 
>>> 
>>>> Am 30.07.2019 um 17:21 schrieb H. Nikolaus Schaller <
>>>> hns at goldelico.com>:
>>>> 
>>>> Hi,
>>>> 
>>>>> Am 30.07.2019 um 16:29 schrieb N. Jackson <
>>>>> nljlistbox2 at gmail.com>:
>>>>> 
>>>>> At 10:22 +0200 on Tuesday 2019-07-23, H. Nikolaus Schaller
>>>>> wrote:
>>>>>> a) the AESS patches by Peter we are carrying along did no
>>>>>> longer compile.
>>>>>> 
>>>>>> Reason is that some members of the dai_link struct have
>>>>>> been replaced by pointers to other structs. The macros
>>>>>> used to initialize them can no longer be used.
>>>>>> 
>>>>>> Therefore I have simply disabled the offending code
>>>>>> lines.
>>>>>> 
>>>>>> Note: this is not yet fixed in the letux/pyra-minimal tree.
>>>>>> 
>>>>>> Generally we need someone who looks at this code pile
>>>>>> and brings them into a better shape. Ideally it would
>>>>>> be made working incl. AESS firmware load and pushed
>>>>>> upstream :)
>>>>> 
>>>>> What is the rationale for the AESS patches in Letux? Does Linux
>>>>> currently have no AESS support, or do these patches modify
>>>>> existing Linux AESS support? If the latter, are the AESS
>>>>> patches
>>>>> in Letux fixing bugs or adding features?
>>>> 
>>>> No, there is no AESS in kernel.org. Andrej did port an older
>>>> version written by Peter (CC:) and I made it work (well compile)
>>>> again on newer mainline kernels.
>>>> 
>>>> What is not working is firmware loading.
>>>> 
>>>> And there are bugs in the integration (API to setup DAI links
>>>> etc.
>>>> has changed).
>>>> 
>>>> So we carry that code along in the hope that Peter or someone
>>>> else finds the time to fix the issues introduced by not having
>>>> it upstream.
>>>> 
>>>>> If the former (no existing AESS support in Linux), then does
>>>>> the
>>>>> hardware targeted by Letux not have audio capabilities
>>>>> (alternative to AESS) for which there is existing support in
>>>>> Linux?
>>>> 
>>>> Yes. Of course. Think of it as a coprocessor like a GPU.
>>>> 
>>>> Without AESS we can use the upstream twl6040 driver directly
>>>> and use it as a simple sound card through aplay. This is the
>>>> status you get if you use omap2plus_defconfig and/or build a
>>>> kernel for Pandaboard or OMAP5EVM.
>>>> 
>>>> But AESS has some nice features:
>>>> * can run independently of OMAP5
>>>> * allows to mix headset, modem audio, bluetooth microphone etc.
>>>> i.e. between all McBSP interfaces
>>>> * audio filters
>>>> 
>>>> These features make it interesting to use. But: this needs a
>>>> binary blob (like GPU or WiFi chips), which is a no-go for FLOSS
>>>> purists.
>>>> 
>>>> BTW: the OMAP4 + twl6040 (PandaBoard) has the same AESS.
>>>> 
>>>> BR,
>>>> Nikolaus
>>>> 
>>>> _______________________________________________
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>>>> Letux-kernel mailing list
>>>> Letux-kernel at openphoenux.org
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>>> 
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>> 
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> -- 
> Mit freundlichen Grüßen,
> 
> Michael Mrozek
> 
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