Re: [PATCH] HID: sony: disable descriptor fixup for FutureMax Dance Mat

From: Antonio Ospite
Date: Mon Jul 25 2016 - 07:06:04 EST

On Mon, 25 Jul 2016 11:14:04 +0200
Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> wrote:

> On Jul 21 2016 or thereabouts, Antonio Ospite wrote:
> > It would be interesting to understand why some (supposedly) compatible
> > devices break, maybe they rely on the fact that the PS3 would use the
> > original report?
> [just speculating]
> I would be *really* surprised if the Sony software were to overwrite the
> report descriptor of their own sony controllers. My guess is that their
> HID stack or their Playstation driver is compatible with the original
> report descriptors and so they can handle the differences between
> original and weirdo controllers.

That's basically what I was thinking too, in my last sentence I meant
to write report _descriptor_ :)

Mikko, if you have some time, could you post the original report
descriptor for your device?

$ hexdump /sys/bus/hid/devices/XXXX\:YYYY\:ZZZZ.0001/report_descriptor


$ hidrd-convert -i natv -o code /sys/bus/hid/devices/XXXX\:YYYY\:ZZZZ.0001/report_descriptor

You can also find out the length of the raw output report with trial and
error, start with a line like this:

$ sudo hexdump -v -e '49/1 "%02x " "\n"' /dev/hidraw0

and increase/decrease the value (49 works with original controllers)
until you see a regular pattern when comparing lines.

Anyways this is just for curiosity, we are not going to spend too much
time on that... or are we? :)


Antonio Ospite

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?