From mboxrd@z Thu Jan  1 00:00:00 1970
From: Laurent Epinat <l.epinat@free.fr>
Subject: Re: New sound device question
Date: Sun, 26 Dec 2010 21:11:32 +0100
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To: Clemens Ladisch <cladisch@fastmail.net>
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Hello

Thanks for the answer




Le 26.12.2010 12:20, Clemens Ladisch a =E9crit :
> Laurent Epinat wrote:
>> I try to developpe a usb sound driver for a Alesis Multix 8 USB2.0
>>
>> http://www.alesis.com/multimix8usb20
>>
>> The output interface is allready fonctional, but the Input not :-(
>> Because there is 2 end point for it. The first one is on Isochronous
>> mode and the other is on Bulk mode
>>
>> I don't know how to declare the second endpoint in the quirks_table.
>
> There is no predefined quirk for such an endpoint; you'd have to write
> your own code.
>
>> Where can I get a good documentation or help about the alsa USB sound
>> structure.
>
> At the moment, the only documentation is the source code.
>
>> The only informations I have about the devices, are dump from windows
>
> What is the bulk endpoint used for?

I don't know exactly,
I think the Isochrone endpoint is used for control and the bulk one is =

the data, because the size is bigger and the interval is short than the =

isochrone one

on the device you can record 10 inputs channels at the same time

Interface Descriptor:
    bLength                 9
    bDescriptorType         4
    bInterfaceNumber        1
    bAlternateSetting       1
    bNumEndpoints           2
    bInterfaceClass       255 Vendor Specific Class
    bInterfaceSubClass      0
    bInterfaceProtocol      0
    iInterface              0
    Endpoint Descriptor:
       bLength                 7
       bDescriptorType         5
       bEndpointAddress     0x81  EP 1 IN
       bmAttributes            5
         Transfer Type            Isochronous
         Synch Type               Asynchronous
         Usage Type               Data
       wMaxPacketSize     0x0040  1x 64 bytes
       bInterval               4
    Endpoint Descriptor:
       bLength                 7
       bDescriptorType         5
       bEndpointAddress     0x86  EP 6 IN
       bmAttributes            2
         Transfer Type            Bulk
         Synch Type               None
         Usage Type               Data
       wMaxPacketSize     0x0200  1x 512 bytes
       bInterval               1




> Regards,
> Clemens
>


-- =

Salutations