Re: [PATCH] Autocentering support for Logitech MOMO Racing Wheel (force feedback)

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Sergey,

On Mon, Aug 18, 2008 at 01:17:48PM +0400, ???????????? ?????????????? wrote:
> Hello.
>   Current kernel has no support for autocentering for Logitech wheels.
> By default autocentering enabled in wheel and constant effect does not
> work properly. Using USB sniffer I found command which change
> autocentering settings: 0xFE, 0x0D, 0x0R, 0x0L, 0x80, 0x00, 0x00,
> where R - clockwise force, L - counter-clockwise (0x0-0xF, 0xC =
> 100%). I write patch for my current kernel (2.6.25), but I think git
> version also supported, because I do not found any changes in it.
> Currently kernel interface has no support for separate autocenter
> control and so I do not implement it.
>   And some interesting command 0xF3 (or 0xF5 - I do not understand
> difference) which makes wheel very easy to rotate (a-la wheel booster
> - no any resistance). Effect of that command can be disabled by
> setting any (zero too) autocentering strength. I do not found in
> kernel interface any standart command for this feature.

This could probably implemented via a sysfs device knob...

> 
>  	error = input_ff_create_memless(dev, NULL, hid_lgff_play);
>  	if (error)
>  		return error;
> 
> +	if (autocenter && dev->ff && (!dev->ff->set_autocenter))
> +		dev->ff->set_autocenter = hid_lgff_set_autocenter;
> +

You can just do "if (test_bit(FF_AUTOCENTER, dev->ffbit))" and you
won't need a temp variable. Also why do you need the rest of the check?

-- 
Dmitry