Re: [PATCH v2 0/2] sunxi, usb: UDC/DM gadget model support

John Watts
2024-04-11T23:36:20Z

On Thu, Apr 11, 2024 at 03:53:51PM -0600, Sam Edwards wrote:
> Hi John,

Hi Sam,

> Ahh I see the problem. In U-Boot, `ubi` isn't actually a block device:
> it's implemented as a stub in the block layer, and the filesystem
> layer redirects `ubi` accesses to the currently-mounted ubifs instead.
> But the `ums` command works on the block layer, so it's not being
> intercepted, and instead hitting that stub and likely crashing. In the
> spirit of the Linux ubiblock driver, I have another patchset[1] I've
> been working on[2] to expose static ubivols as true read-only block
> devices. Note that this only works for static volumes: the access
> semantics of dynamic volumes are too flash-like to support block
> device access, so accessing them with `ums` likely will never work
> like users expect.

I'll give a patchset a test when I can.

> Still, there could be some interaction issue between `ums`<->USB that
> I haven't identified. Could you try with mmc (if available) or a
> ramdisk (otherwise) just to confirm that `ums` is fine?

I'll try testing with those if possible.

I did find out that fastboot actually works, and is much, much faster than DFU
for some reason.

John.

>
> Regards,
> Sam
>
> [1] https://lore.kernel.org/u-boot/20230812000606.72319-1-CFSworks@gmail.com/T/
> [2] Not very diligently; if you're interested in helping test it, I'd
> love to get back to it.