Re: [PATCH] Force feedback support for uinput

From: aris
Date: Fri Nov 12 2004 - 07:10:34 EST

> Hello,

> This patch adds support to uinput for Linux's force feedback interface.
> With these changes, it's possible to write drivers for force feedback
> joysticks and similar devices in userspace. It also adds a way to set
> the physical path of devices created via uinput, and it has a couple
> trivial bugfixes.

> My solution is to have a special input event, outside the range
> defined by the input system, that uinput sends to the application
> to signal when a callback has been entered. A particular callback
> invocation is identified by a request ID stored in this event.
> +/* This is the new event type, used only by uinput.
> + * 'code' is UI_FF_UPLOAD or UI_FF_ERASE, and 'value'
> + * is the unique request ID. This number was picked
> + * arbitrarily, above EV_MAX (since the input system
> + * never sees it) but in the range of a 16-bit int.
> + */
> +#define EV_UINPUT 0x0101
I guess it should be moved to input.h with other types of events.

> +/* To write a force-feedback-capable driver, the upload_effect
> + * and erase_effect callbacks in input_dev must be implemented.
> + * The uinput driver will generate a fake input event when one of
> + * these callbacks are invoked. The userspace code then uses
> + * ioctls to retrieve additional parameters and send the return code.
> + * The callback blocks until this return code is sent.
what about moving this long comment to Documentation/input/uinput.txt?

the rest of the patch seems fine to me


(p.s.: sorry for the delay and the dup that will follow. my server is
offline due adsl problems and the first answer is stuck there :)


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