Re: [REGRESSION] "USB: use kfifo to buffer usb-generic serial writes" causes gobi_loader to hang

From: Anssi Hannula
Date: Mon Feb 22 2010 - 14:24:40 EST


On maanantai 22 helmikuu 2010 21:10:33 Alan Stern wrote:
> On Mon, 22 Feb 2010, Anssi Hannula wrote:
> > I guess that would suggest that the device doesn't allow the
> > initialization data to be broken into packets arbitrarily (though some
> > differences seem allowed, as the windows driver transmits them
> > differently).
> >
> > Does this mean a tty interface is ill-suited for the microcode upload,
> > and instead qcserial should use the kernel's generic microcode upload
> > mechanism or the userspace should use libusb to do it?
>
> I don't know. Didn't the old successful code use a tty interface?

Yes, but does the tty interface guarantee that the data of one write call is
sent as one packet to the device?

If I understood this correctly, it seems the changes have caused it to now
concatenate short writes into one packet, which the device doesn't seem to
like.

--
Anssi Hannula
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/