On Fri, 14 Mar 2008, chris guirl wrote: > I have a Logitech Driving Force Pro and I've been trying to figure out > how to make it work better in Linux. I have recently learned some things > about both wheels that would be nice to incorporate into the driver. > Most of this information was gained through a contact at Logitech. I > intend to investigate making some changes to the kernel to improve the > support for these wheels. Two of the main features I'd like to > incorporate are setting the wheel axis range to different values so the > full 900 degree range of the wheel can be used, and providing separated > axes for the gas and brake pedals. So, where to start? I'm not very > familiar with kernel hacking but I'll begin doing some research on it > soon. Can anyone on the list provide me with some guidance? I've tried > to find some driver hacking documentation specific to my task but I > haven't found much. Something along the lines of a joystick or USB > driver hacking tutorial would help me a lot. I've also looked through a > good bit of the Linux joystick and USB HID code in the input section and > I am unsure where device specific code goes. I guess I have some more > reading to do...
Hi Chris, thanks for your mail, I have added Jean-Philippe to CC, who has sent me some time ago debugging information for this wheel, but I unfortunately didn't yet had time to look into that in more detail. Regarding the HID code -- currently, all device-specific stuff for HID devices is implemented as quirks in hid code -- please see drivers/hid/hid-*quirks* and drivers/hid/usbhid/hid-quirks*. This is not a solution that works well in long-term though, and Jiri Slaby (also added to CC) is currently rewriting the HID core code, so that it will work as a proper bus, so individual drivers could work nicely with that. Once this is done, all the current quirks will be converted to HID-bus drivers. Depends on how massive your changes are going to be, you could either coordinate with Jiri so that no effort is wasted, or you can just send me a patch with simple quirks addition, and it will get converted into hidbus driver later. Thanks, -- Jiri Kosina SUSE Labs
