Hi On Sat, Sep 7, 2013 at 11:20 AM, Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx> wrote: > > > On 07/09/13 10:57, David Herrmann wrote: >> Hi >> >> On Sat, Sep 7, 2013 at 10:24 AM, Benjamin Tissoires >>> I'm not particularly in favor of adding semantic between ABS_MISC and >>> ABS_MT_SLOT. We already did that once with the ABS_MT_* stuff, and the >>> problem comes from devices showing several axes, not really mapped >>> (like joysticks). These axes are all mapped to ABS_MISC, but the input >>> core function map them to ABS_MISC+N. This way some joysticks show >>> multitouch axes and are treated as such, whereas the axis are just >>> regular absolute axes. (not sure I am clear enough... :( ) >>> >>> Currently, nothing is done in X or in Wayland to detect these false >>> multitouch devices with a large number of absolute axes. But if we >>> keep a hole between ABS_MISC and ABS_MT_SLOT, we could add an >>> heuristic like: >>> "if all the axes between ABS_MISC and ABS_MT_SLOT are available, then >>> ABS_MT_SLOT does not mean multitouch, but ABS_MISC+6." >> >> So Xorg just took control over the unused ABS_* slots? Hmm, then I >> have no other idea than reverting the 3 patches. >> Sadly, that also means there's no way for us to easily extend the >> ABS_* bits. If someone has an idea, let me know. But for now I'll just >> put the drums/guitar patches on hold. >> > > Well, I would say the "problem" lies in hid-input.c, line 919: >>>>>>>>>>>>>>>>>>> > while (usage->code <= max && test_and_set_bit(usage->code, bit)) > usage->code = find_next_zero_bit(bit, max + 1, usage->code); >>>>>>>>>>>>>>>>>>> > > So if you try to map several times ABS_MISC or any other axis, then you are mapping ABS_MISC+N. > > Anyway, the only problematic axis is ABS_MISC, as it is a default fallback. IMO, we can extend the ABS_* definitions after ABS_MT_TOOL_Y, like the original patch you proposed without having to deal with the above problem (though this will report the patch series to v3.13). > To prevent future mistakes, we should just define ABS_MISC0 (0x29) to ABS_MISC5 (0x2e) to fill the hole. As mentioned earlier in this thread, ABS_* is limited to 0x3f, so we have only 2 more free slots after ABS_MT_TOOL_Y. We will figure something out for 3.13. I will also prepare a patch for ABS_MISC0-MISC5. Regards David -- 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
