Re: [PATCH v5 5/8] usb: mausb_host: Introduce PAL processing

From: Alan Stern
Date: Sat Apr 25 2020 - 20:32:12 EST


On Sat, 25 Apr 2020 vladimir.stankovic@xxxxxxxxxxxxxxx wrote:

> Protocol adaptation layer (PAL) implementation has been added to
> introduce MA-USB structures and logic.
>
> Signed-off-by: Vladimir Stankovic <vladimir.stankovic@xxxxxxxxxxxxxxx>

...

> + /*
> + * Masking URB_SHORT_NOT_OK flag as SCSI driver is adding it where it
> + * should not, so it is breaking the USB drive on the linux
> + */
> + urb->transfer_flags &= ~URB_SHORT_NOT_OK;

Removing the SHORT_NOT_OK flag is _not_ a valid thing to do. It will
cause drivers to malfunction.

Can you please explain this comment?

What SCSI driver?

When is the flag being added?

How does it break USB drives?

Why haven't you already reported this problem to the
appropriate maintainers?

Alan Stern