Re: missing USB gadget support on beagleboard?

[Hollis Blanchard <hollis_blanchard@mentor.com>]

On 02/15/2012 04:35 PM, Bruce Ashfield wrote:
> On 12-02-15 06:20 PM, Hollis Blanchard wrote:
>> On 02/14/2012 10:24 PM, McClintock Matthew-B29882 wrote:
>>> On Tue, Feb 14, 2012 at 4:12 PM, Hollis Blanchard
>>> <hollis_blanchard@mentor.com> wrote:
>>>> Hi, I'm sure I'm missing something simple, but I just built Poky from
>>>> git
>>>> for beagleboard, and can't figure out USB networking. I expected to 
>>>> find
>>>> g_cdc and g_ether modules in
>>>> /lib/modules/3.0.18-yocto-standard+/kernel/drivers/usb, but that
>>>> directory
>>>> doesn't actually exist (I guess the drivers are built-in to this
>>>> kernel).
>>>>
>>>> I have MACHINE ??= beagleboard in local.conf, and "bitbake
>>>> core-image-minimal" did produce a working kernel, uboot, etc. I see
>>>> some USB
>>>> messages at boot (see below), but although cdc_ether is mentioned,
>>>> ifconfig
>>>> -a lists only loopback.
>>>>
>>>> Any suggestions? Thanks!
>>> You can look at the default defconfig to see which kernel modules are
>>> selected and also make sure the kernel modules are actually included
>>> on core-image-minimal.
>>
>> Right, it looks like CONFIG_USB_ETH is disabled in
>> linux-beagleboard-standard-build/.config , and I think that's the key
>> missing option. I'm so lost in Yocto's kernel configuration
>> "architecture" that I have no idea if that's being explicitly disabled,
>> or just omitted from the base config, or what.
>
> Is this the 3.0 variant ? That particular option wasn't enabled (most
> likely because no one had the right device to test it). But that's not
> the point, we can absolutely and easily enable it .. in particular
> if someone confirms that it works :)

Yes, it's (apparently) a 3.0.18 kernel. I'd be happy to test it.

>> It seems to me that option should be enabled if DISTRO_FEATURES contains
>> usbgadget. More simply, it seems like a good idea to enable
>> CONFIG_USB_ETH in the beagleboard default configuration, since many
>> beagleboards don't have any other network interface.
>
> The ethernet issue(s) are a painful memory of last year's ELC demos and
> plenty of swearing about USB ethernet that didn't detect due to 
> particular
> USB hubs.

I don't think I can do anything about that. :)

> We can trigger the inclusion of a particular config option or fragment
> directly from a distro feature as well.

Matt's clues may have helped me decipher enough to create a 
features/usb-gadget fragment. AFAICS, that can't be controlled by 
bitbake variables... but it would be enough for me. :)

The next issue is something to auto-load the g_ether module at boot. It 
looks like there's no shortage of init scripts developed for this 
purpose in different OE distributions, but none of them are installed in 
Yocto's Beagleboard build...

>> Is there an owner of Yocto's beagleboard BSP stuff?
>
> I can help. Sorry that I missed your first email, traveling to ELC
> filled up my inbox with a backlog.

No worries, I knew it was a bad time to ask... thanks!

Hollis Blanchard
Mentor Graphics, Embedded Systems Division