On Wed, 1 Dec 2010 13:23:15 -0500 simon@xxxxxxxxxxxxx wrote: > I am working on a driver for a Logitech gaming wheel where the HID > descriptor presents a 'joystick' with X and Y axis, the Y is a combined > acc/brake value even though the wheel has separate paddles for each. > > There are 'vendor defined' variables for both the acc/brake within the HID > descriptor, but these are not (by Linux) tied to their function. > > On the Windows, the specialised Logitech driver gives the option to use > either combined or separate acc/brake. > > I am considering re-writing the HID descriptor to expose these separate > values as 'proper' axis, as they would provide both better resolution and > better functionality (ie. left foot braking). > Simon, have you tried Marcin Tolysz's approach of loading the new HID descriptor from an external file? Look at: https://patchwork.kernel.org/patch/69723/ If there is interest maybe Marcin's way could be brought back on the discussion table (Marcin added to CC). I'll be needing descriptor patching for Sony Sixaxis too, after I solved some other issues, so I am also interested on settling on a "standard" way to achieve that. > Q1. Is this an acceptable thing to do? > > Q2. In the case where there is significant change to the HID descriptor, > is it OK to just re-write the whole block (rather than patch/swap a couple > of bytes)? > > Q3. In re-writing descriptor for the combined acc/brake. Is there a > particular 'variable' I should change it to (X, Y and Z would already be > used), or should I just make it 'vendor defined'? > > Thanks in advance, > Simon > (aka Mungewell) > Regards, Antonio -- Antonio Ospite http://ao2.it PGP public key ID: 0x4553B001 A: Because it messes up the order in which people normally read text. See http://en.wikipedia.org/wiki/Posting_style Q: Why is top-posting such a bad thing?
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