Re: [PATCH 06/13] USB: serial: ch341: fix initial line settings

[Johan Hovold <johan@kernel.org>]

On Mon, Dec 19, 2016 at 08:40:53AM -0800, Russell Senior wrote:
> On Mon, Dec 19, 2016 at 2:58 AM, Johan Hovold <johan@kernel.org> wrote:
> > On Sat, Dec 17, 2016 at 03:27:43AM -0800, Russell Senior wrote:
> >> All testing is with minicom.
> >
> > Thanks for this through report.
> >
> >> Starting with 00013-gc510871:
> >>
> >>   In 8-bit mode, interoperates correctly with pl2303.  Switching to
> >> 5-bit mode on both sides (I get unicode boxes of indeterminate
> >> values).  Switching back to 8-bit mode on both sides, I get correct
> >> text out both sides.  Switching just the ch341 side back to 5-bit
> >> mode, I get 0xff's out on the pl2303 side (still in 8-bit mode).  This
> >> would seem to imply that byte-size changes are working on this
> >> version.  Changing baud rate also works.
> >
> > Can you verify also what comes through in 5-bit mode is indeed what's
> > expected (e.g. 'a' -> 0x01, 'b' -> 0x02, ...)?
> >
> > You can enable usb-serial debugging to get a log of what is received:
> >
> >         modprobe usbserial dyndbg==p
> >
> 
> Yes, it does seem that I'm getting the 5-bit truncation.  Here is an
> excerpt from the prodigious logs, in this case sending a 'Z' from
> pl2303 and receiving an 0x5a on the ch341.  The same sort of thing,
> e.g. 'A' (0x41) from the ch341 lands as an 0x01 on the pl2303, 0x42 ->
> 0x02, etc.

Thanks for confirming.

> > Ok, so the init command cannot be used to switch baud rate for these
> > devices.
> >
> > Could you see if you can communicate using 19200 baud (when using this
> > or the next commit), which is the default baud rate for the devices I
> > have (i.e. default settings are 19200 8N1).
> 
> 19200 8N1 on this commit does not work.

Ok.

Johan