From: Ruslan Bilovol <ruslan.bilovol@gmail.com>
To: Krzysztof Opasiak <k.opasiak@samsung.com>
Cc: Jassi Brar <jassisinghbrar@gmail.com>,
Clemens Ladisch <clemens@ladisch.de>,
Felipe Balbi <balbi@kernel.org>, Daniel Mack <zonque@gmail.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 0/5] USB Audio Gadget refactoring
Date: Wed, 27 Jul 2016 00:55:17 +0300 [thread overview]
Message-ID: <CAB=otbTkg9bU0=-z8D78ajkf8soxO4Q41KgH1ew5FTgrgPw4xQ@mail.gmail.com> (raw)
In-Reply-To: <57975146.5090501@samsung.com>
On Tue, Jul 26, 2016 at 3:02 PM, Krzysztof Opasiak
<k.opasiak@samsung.com> wrote:
>
>
> On 07/26/2016 10:53 AM, Jassi Brar wrote:
>> On Tue, Jul 26, 2016 at 7:01 AM, Ruslan Bilovol
>> <ruslan.bilovol@gmail.com> wrote:
>>> On Fri, Jul 15, 2016 at 10:43 AM, Clemens Ladisch <clemens@ladisch.de> wrote:
>>>>>> On Tue, May 24, 2016 at 2:50 AM, Ruslan Bilovol
>>>>>> <ruslan.bilovol@gmail.com> wrote:
>>>>>>> it may break current usecase for some people
>>>>
>>>> And what are the benefits that justify breaking the kernel API?
>>>
>>>
>>> Main limitation with current f_uac1 design is - it can be used only on systems
>>> with real ALSA card present and can have only exact number of
>>> channels / sampling rate as sink card has.
>>> Yet it is not flexible - can't do audio processing between f_uac1 and the card.
>>> Also if someone wants to bind f_uac1 it to another sound card he has to
>>> unload g_audio or reconfigure it through configfs - that means USB
>>> reenumeration on host device.
>>>
>>> If you have a "virtual sound card", audio processing is done in userspace
>>> and is more flexible. You even don't need to have a real sound card and
>>> can use some userspace application for playing/capturing audio samples.
>>> Moreover, existing f_uac2 (that is USB Audio Class 2.0 function
>>> implementation) already uses approach of "virtual sound card"
>>>
>> While I agree the virtual sound card approach is the right way, I am
>> not sure if we should break the userspace api that the existing UAC1
>> driver exposes. Maybe we should add another virtual-sound-card
>> exposing UAC1 driver ... and hopefully very similar to (or just port
>> of) the f_audio_source.c from android.
>
> Definitely agree with this opinion. I don't see any benefits of breaking
> the API here instead of adding just another USB function. Maybe even
> some pieces of code could be shared with f_uac1.c but I think that this
> should be a brand new function.
>
So if we want to keep old API working, easiest (and cleanest) way is
to create a new f_uac1.c version and kconfig symbol, for example
f_uac1_newapi.c and CONFIG_USB_F_UAC1_NEWAPI
There is no sence to share some pieces of code with f_uac1.c just
because it is changed too drastically.
So I'll implement it in v2 if there is no any objections
Best regards,
Ruslan Bilovol
next prev parent reply other threads:[~2016-07-26 21:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-23 23:50 [RFC PATCH 0/5] USB Audio Gadget refactoring Ruslan Bilovol
2016-05-23 23:50 ` [RFC PATCH 1/5] usb: gadget: f_uac2: remove platform driver/device creation Ruslan Bilovol
2016-05-23 23:50 ` [RFC PATCH 2/5] usb: gadget: f_uac2: split out audio core Ruslan Bilovol
2016-05-23 23:50 ` [RFC PATCH 3/5] usb: gadget: f_uac1: drop volume/mute functionality Ruslan Bilovol
2016-05-23 23:50 ` [RFC PATCH 4/5] usb: gadget: f_uac1: switch to u_audio core utilities Ruslan Bilovol
2016-05-23 23:50 ` [RFC PATCH 5/5] usb: gadget: f_uac1: add capture support Ruslan Bilovol
2016-06-08 8:03 ` [RFC PATCH 0/5] USB Audio Gadget refactoring Ruslan Bilovol
2016-07-14 21:38 ` Ruslan Bilovol
2016-07-15 7:43 ` Clemens Ladisch
2016-07-26 1:31 ` Ruslan Bilovol
2016-07-26 8:06 ` Clemens Ladisch
2016-07-26 21:22 ` Ruslan Bilovol
2016-07-26 8:53 ` Jassi Brar
2016-07-26 12:02 ` Krzysztof Opasiak
2016-07-26 21:55 ` Ruslan Bilovol [this message]
2016-07-26 21:38 ` Ruslan Bilovol
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