Re: [PATCH] USB: serial: simple: narrow OWON match to avoid breaking VDS1022

[Huang Wei]

Hi Craig,

Thanks for the additional data points - and for the comprehensive
descriptor table. This changes the picture significantly.

The VDS1022I reporting (5, 0, 0) - the same tuple as the HDS200 -
means the full-tuple match in my v2 doesn't actually solve the
problem it was designed for. It would:

  - correctly claim the HDS200 (which wants serial)
  - incorrectly claim the VDS1022I (which needs libusb, same
    florentbr tooling as the VDS1022)

So the interface tuple is not a reliable discriminator for this
VID:PID - OWON reuses the same tuples across device families with
different userspace needs. That undermines any approach based on
narrowing the match at the interface level.

Given this, I think the options are:

  1. Keep the original broad USB_DEVICE() match, accepting that
     VDS1022/VDS1022I users need to blacklist the driver (this was
     the status quo before my patches, and users have workarounds)

  2. Remove the owon entry entirely and have HDS200 users move to
     libusb as well (uniform but breaks existing serial users)

  3. Find a different discriminator (bcdDevice, string descriptors)
     - but these seem equally unlikely to be reliable given OWON's
     firmware practices

Johan - given that the interface-level narrowing doesn't work,
what's your preference? Should we revert to the original match and
document the libusb incompatibility, or is there another approach?

Thanks,
Huang Wei