Re: [Line6linux-user] The HD500

[Steve U. <st...@co...>]

On 06/13/2011 03:09 AM, Markus Grabner wrote:
> On Sunday 12 June 2011 10:49:34 Steve Underwood wrote:
>> Hi,
>>
>> Has there been any work towards supporting the HD series PODS? I can't
>> see any mention of these newer boxes in the code. I am wondering just
>> how different they are, and whether support actually requires a whole
>> new set of drivers. I'm fairly sure the user space code is going to be a
>> lot different.
> I'm not aware of any work towards HD support, and since I don't have one,
> there is little chance that I can contribute. However, if you take the time to
> create some USB traffic logs, I can at least roughly assess how different the
> HDs' communication is compared with the supported devices. Please have a look
> at http://www.tanzband-scream.at/line6/usblog.html for instructions how to
> obtain this information, and send the files to me if you are successful
> producing them. The result can be anything between "Oh, it's almost the same
> as the PODxt Pro" to "Hm, I can't proceed without an HD for experimenting
> myself", so there is no guarantee that your efforts will pay off, although it
> would be definitely interesting to have a look.
>
> 	Thanks&  kind regards,
> 		Markus
>
I finally had some time to work on this. I did a little snooping, with 
USB snoop, and I have done some work deciphering the tone data.

The audio looks like it is probably similar to the X3 and X3PRO, since 
it uses the same end points (0x02 and 0x86), while all the other PODs 
appear to use other endpoints. However, it looks like X3 and X3PRO 
support in the driver is incomplete. I added the HD500's USB ID to the 
driver. When I plug in the HD500 I get 2 card directories in 
/proc/asound, but these devices are not listed in /proc/asound/devices 
or /proc/asound/cards. I'm not that familiar with the Linux USB and ALSA 
mechanisms, so it might take quite a bit of study for me to get much 
further.

The control also looks like it may resemble the X3 and X3PRO, as it uses 
the same end points (0x01 and 0x81). I can follow the control 
information with my limited USB knowledge. I've done quite a bit of work 
figuring out the details of the tone data. The data exchanged with the 
POD is basically the same as the data stored in the tone files. They 
byte reverse all the floating point values in the files, and a few bits 
seem to be different, but the great majority is the same. I worked my 
way through the parameters and I now know what most of the data in the 
tone files actually means. I have a crude program which can dump it out.

If there is any available information which might help make the audio 
spring to life, that would be extremely useful.

Steve