Hi Bastien, On Tue, May 29, 2018 at 12:17 PM, Bastien Nocera <hadess@xxxxxxxxxx> wrote: > Hey, > > Ethan recently posted a patch to SDL's GameControllersDB to fix up > buttons on his GPDWin 2: > https://twitter.com/flibitijibibo/status/1000835085891973127 > > There are a couple of problems with this approach though: > - it only works with SDL, not with any other possible users of the > joystick API > - the parsing code depends on the SDL library, again problematic for > non-SDL programs > > There are advantages as well: > - it's easy to write and test, there are test applications using SDL, > and fixing the problem is as easy as sharing a single line to add to a > file > - the documentation is pretty good: > https://github.com/gabomdq/SDL_GameControllerDB > which is better than: > https://www.kernel.org/doc/Documentation/input/joydev/joystick.rst > > Can we think of a way where writing and testing "fixups" is easy enough > to do without having a kernel development tree ready, documentation > would better explain the different cases for fixups, and everybody can > benefit from having quirks written? One thing that comes to my mind is that in evdev we have the ability to remap a button/key from the userspace with an ioctl. If it doesn't work for joysticks/gamepads, we should be able to have an API that does it in the kernel and with a udev rule, or a hdwdb or a udev intrinsic, we could just remap to the proper keys without relying on an external lib. Ideally, this should be carried (the hwdb / udev intrinsic) by SDL developers so they can smoothly transition from their own file format to a kernel fix. OTOH, we had a somewhat similar issue with the Wacom devices. We ended up having libwacom which provides a standalone library with those data that any project can link against and use at will. So Maybe a solution could be to ask the SDL devs to externalize this DB and have something other projects can rely on. You understand, I am not much in favor of fixing directly things in the kernel, because you will end up breaking existing user configs, for little benefits. I only agree with kernel fixes if the device doesn't work or has missing features. Cheers, Benjamin -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
