[v2,0/8] lsusb: Add initial support for USB Audio Class 3

[Michael Drake <michael.drake@codethink.co.uk>]

On 07/12/17 20:04, Greg KH wrote:
> On Thu, Dec 07, 2017 at 07:24:35PM +0000, Michael Drake wrote:
>> On 07/12/17 17:26, Greg KH wrote:
>>> On Thu, Dec 07, 2017 at 05:14:10PM +0000, Michael Drake wrote:
>>>> On 07/12/17 15:16, Greg KH wrote:
>>>>> On Thu, Dec 07, 2017 at 04:01:23PM +0100, Greg KH wrote:
>>>>>> Oops, I should have tested the code, it now crashes for me with the
>>>>>> following error:
>>>>>> 	Floating point exception (core dumped)
>>>>>>
>>>>>> Do you see this as well?
>>>>
>>>> No, I don't see that.
>>>>
>>>>> And it's crashing on my USB audio device.  Here's the output of it from
>>>>> the "old" lsusb output.
>>>>
>>>> [snip]
>>>>
>>>> Does it still crash with the warning fixes I posted?  If so I'll
>>>> look in detail tomorrow.
>>>
>>> I will check when I get home tonight, I don't have the USB device on me
>>> at the moment.
>>
>> Thank you.  I believe I've guessed the problem and sent a patch.
> 
> Ok, that now works.
> 
> But there is a difference in the "old" and "new" outputs, here's a diff
> of a full -v output of my laptop and a bunch of USB devices plugged in,
> showing the fields that now look different.
> 
> The big one is the change from "streaming" to "control", is that
> correct?

Replied inline below.

> thanks,
> 
> greg k-h
> 
> 
> --- lsusb-v.orig	2017-12-07 21:01:26.153185002 +0100
> +++ lsusb-v.new	2017-12-07 21:01:32.806517978 +0100
> @@ -1110,9 +1110,9 @@
>           bDescriptorType        36
>           bDescriptorSubtype      1 (HEADER)
>           bcdADC               1.00
> -        wTotalLength       0x0028
> +        wTotalLength           40

I was a bit confused by this diff at first, because the
"-" lines are my version and the "+" lines are the old
version.

Anyway, this is expected.  For NUMBER type fields, my
code uses the heuristic that 1 byte fields are shown as
decimal and >1 byte is shown as full hexadecimal, with
leading zeros shown.  This is consistent with the way
the old lsusb behaved in most cases, although it was
slightly inconsistent about it, and this is an example
of that inconsistency.

Anyway, since it's a 2 byte field the hex representation
is expected here, and the actual value is the same.


>           bInCollection           1
> -        baInterfaceNr(0)        1
> +        baInterfaceNr( 0)       1

Just a whitespace change.  My version's not using
a fixed width for the array index, and only uses what's
needed for the largest index to be represented.

>         AudioControl Interface Descriptor:
>           bLength                12
>           bDescriptorType        36
> @@ -1142,10 +1142,10 @@
>           bUnitID                13
>           bSourceID               1
>           bControlSize            1
> -        bmaControls(0)       0x01
> +        bmaControls( 0)      0x01
>             Mute Control
> -        bmaControls(1)       0x00
> -        bmaControls(2)       0x00
> +        bmaControls( 1)      0x00
> +        bmaControls( 2)      0x00

Ditto for these.

>           iFeature                0
>       Interface Descriptor:
>         bLength                 9
> @@ -1173,7 +1173,7 @@
>           bDescriptorSubtype      1 (AS_GENERAL)
>           bTerminalLink           1
>           bDelay                  1 frames
> -        wFormatTag         0x0001 PCM
> +        wFormatTag              1 PCM

This is the >1 byte shown as hexadecimal thing.

>         AudioStreaming Interface Descriptor:
>           bLength                20
>           bDescriptorType        36
> @@ -1199,14 +1199,14 @@
>           bInterval               4
>           bRefresh                0
>           bSynchAddress         133
> -        AudioStreaming Endpoint Descriptor:
> +        AudioControl Endpoint Descriptor:

This is from the dump_audiostreaming_endpoint() function.
The "AudioStreaming" string is correct.  Looks like a typo
in the old lsusb output.

>             bLength                 7
>             bDescriptorType        37
>             bDescriptorSubtype      1 (EP_GENERAL)
>             bmAttributes         0x01
>               Sampling Frequency
>             bLockDelayUnits         0 Undefined
> -          wLockDelay         0x0000
> +          wLockDelay              0 Undefined

This and the remaining entries are similar to the above ones.

>         Endpoint Descriptor:
>           bLength                 9
>           bDescriptorType         5
> @@ -1235,7 +1235,7 @@
>           bDescriptorSubtype      1 (AS_GENERAL)
>           bTerminalLink           1
>           bDelay                  1 frames
> -        wFormatTag         0x0001 PCM
> +        wFormatTag              1 PCM
>         AudioStreaming Interface Descriptor:
>           bLength                20
>           bDescriptorType        36
> @@ -1261,14 +1261,14 @@
>           bInterval               4
>           bRefresh                0
>           bSynchAddress         133
> -        AudioStreaming Endpoint Descriptor:
> +        AudioControl Endpoint Descriptor:
>             bLength                 7
>             bDescriptorType        37
>             bDescriptorSubtype      1 (EP_GENERAL)
>             bmAttributes         0x01
>               Sampling Frequency
>             bLockDelayUnits         0 Undefined
> -          wLockDelay         0x0000
> +          wLockDelay              0 Undefined
>         Endpoint Descriptor:
>           bLength                 9
>           bDescriptorType         5
> 

Cheers,