On Fri, Mar 14, 2008 at 5:42 AM, Jiri Kosina <jkosina@xxxxxxx> wrote: > 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. Which wheel, the DFP or the G25? Either way they are similar in many ways so better support for one would improve support for the other. I'm interested to see this information. There has been some discussion of the G25 on the forums at vdrift.net. > 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. I've looked through the quirks code and I have some suggestions for things that can be changed. First, the Vendor/product IDs of the wheels are not present. When the devices power up they assume VID:PID 0x046d:0xc294 which there is a line for in drivers/hid/usbhid/hid-quirks.c: #define USB_DEVICE_ID_LOGITECH_WHEEL 0xc294 This is used by the Logitech Formula Force or Driving Force wheel, and a legacy mode on the DFP & G25. To use the DFP or G25 in their native modes, they must be sent a command [0xf8, 0x01] or [0xf8, 0x10] respectively. Once these wheels receive this command, they simulate a detach and reattach as 0x046d:0xc298 and 0x046d:0xc299 respectively. These VID:PID combinations are not handled in the kernel at all. At the very least they need to be assigned the same quirks as the Driving Force. When a Driving Force/Formula Force wheel is detected the device needs to be probed with the native mode commands to see if it will switch into DFP or G25 mode. If these modes work, then it is possible to send the wheels some other commands to enable full rotation of the wheel. By default only 200 degrees of rotation is available, but both the DFP and G25 can be switched to allow up to 900 degrees of rotation. I think there should be a user-land tool to change settings on the wheel such as this. > 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. If there is a rewrite due then it may be best to work with Jiri so I can make my changes work with his, no sense in patching twice. In addition to HID code, I think I'll need to make some changes to the joydev driver, as some other things need to be addressed (such as splitting the gas and brake axis up into separate, independent axes). Currently I am able to send raw commands to my DFP to make it change modes, but the /dev/input/jsX device disappears when I do this, so some other tweaks may be needed on the joystick end of things. I'll be out of town this weekend so not working on anything yet, but please send any ideas along as I hope to get started next week. Thanks. Chris -- 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
