Re: [PATCH] Fix autocentering command in hid-lgff driver

[Michael Bauer <michael@m-bauer.org>]

Am 27.06.2011 22:58, schrieb Michal Malý:
>> I think that we need to build a list/matrix and confirm that _all_ wheels
>> are OK with a single set of commands (autocenter for the FX excluded).
> I've tested your modded script and it worked fine with DFP. Peter who asked to be CC'ed too (I added him to CC) tried it
> out in G27 and reported that all was OK.
DFP, G25 and Momo Racing also worked fine on my side.

>> A resent patch (https://patchwork.kernel.org/patch/921052/) for the
>> WiiMote gives a good example how to implement '/sys/' files and we could
>> use these to control the wheel's modes, such as:
>>
>> /sys/bus/hid/drivers/lg4ff/<dev>/native - write 1 to switch to native,
>> read to get current state
>> /sys/bus/hid/drivers/lg4ff/<dev>/range - write angular range, read to get
>> current range
Yes, i also vote for something like this. Just keep in mind that we 
still need to find a reliable way to identify exactly the correct wheel, 
as they all register initially with the same VID/PID but need different 
commands for native mode and range.
This might be possible using the revision number - I am trying to get 
this implemented in ltwheelconf soon to have some more users test if it 
works.

>> Q. Do we need the ability to switch between split/combined pedals?
I am not sure on this - on the one hand i would love to provide all 
options to the user.
On the other hand i am not sure how this could be done. I do not think 
it is possible to change the report descriptor of a connected device on 
the fly without (not necessarily physically) reconnecting it?
And from my understanding the combined axes are just some kind of legacy 
stuff to support really old games which can not handle the separate axes.
So from my opinion we should at least initially just provide separate 
axes and don't try to implement complicated stuff to allow switching to 
combined mode.

> I guess I answered that above, I'd absolutely love to get this into the kernel. Using /sys sounds like the best way to me.
> There are two issues I can think of. First wheels actually simulate reconnect when they're switched to the native mode,
> so I guess we'd have to be careful and not cause any memory leaks and stuff. Second all Logitech wheels short of
> G25/27 need a replaced HID descriptor to get separate pedals working, so unless there's a reasonable way how to read
> the anonymous fields reported in the original descriptor, I say keep the pedals always separate for now.
I agree as stated above :-)

Best regards
Michael
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