Re: mceusb: No keypresses on Formosa Infrared Receiver

[Sean Young <sean@mess.org>]

Hi Patrick,

On Sun, Jan 19, 2025 at 05:34:18PM +0100, Patrick Zacharias wrote:
> Hello there,
> 
> while using the Formos Infrared Receiver (147a:e016), I've noticed, that
> it won't stop blinking and doesn't register any presses.
> This issue appears to have been present since 2019,
> according to a thread on a German VDR forum.

That's interesting, mind sharing a link to the forum discussion please.

Also what does the device look like, it would be useful to get it and
test it myself if possible.

> And appears to be a regression, as according to that thread it used to
> work with their software
> (yavdr-0.6.2, which appears to based on kernel 3.13.0).

A git bisect would be useful.

> I've tried this on 5.16-rc2 (mainline on an X86 machine) and with
> 6.6.62+rpt-rpi-v8 from the latest Raspberry Pi OS.
> 
> I've analyzed a PCAP dump from a Windows 7 machine to see where the
> initialization differs and noticed,
> that an undocumented byte 0xF4 is being sent, after DEVICE_RESUME and
> G_REVISION (which are both sent in one packet).

You mean during device probe?

> By unbinding the driver, manually sending 0xF4 to the device and
> rebinding the driver, I'm able to workaround this issue.
> The blinking is gone and keypresses are now received. (Except for the OK
> key).
> 
> No further testing has been done.
> 
> I'm willing to provide PCAP traces, if of interest.

Yes please :)

Thanks,

Sean