On Wed, Sep 10, 2014 at 04:22:13PM +0200, David Herrmann wrote: > Hi > > On Wed, Sep 10, 2014 at 1:13 PM, Fredrik Hallenberg > <megahallon@xxxxxxxxx> wrote: > > The keyboards in question have n-key rollover, this seems to be > > implemented by sending every single key id every time the keyboard is > > polled, this includes several keys that does not exist physically for > > example 0x31. This may be a bit excessive but not broken. If I press > > a-key and '-key in rapid succession, I get the following events > > (omitting all other keys): > > > > VALUE 1 CODE 30 HID 0x4 > > VALUE 0 CODE 43 HID 0x31 > > VALUE 0 CODE 43 HID 0x32 > > Output: a > > > > VALUE 1 CODE 30 HID 0x4 > > VALUE 0 CODE 43 HID 0x31 - 43 is up > > VALUE 1 CODE 43 HID 0x32 - 43 is down > > Output: ' > > > > VALUE 0 CODE 30 HID 0x4 > > VALUE 0 CODE 43 HID 0x31 - 43 is up > > VALUE 1 CODE 43 HID 0x32 - 43 is down > > Output: ' > > > > VALUE 0 CODE 30 HID 0x4 > > VALUE 0 CODE 43 HID 0x31 - 43 is up > > VALUE 1 CODE 43 HID 0x32 - 43 is down > > Output: ' > > > > So even though the keyboard is behaving a bit weird the problem is in > > the kernel as it will interpret 0x31 and 0x32 as the same key. > > Thanks for the information! Please include that in follow-up > commit-messages so others can see it as well. I don't think a report > descriptor is needed, anymore. > > This indeed explains the problem. We only track keys on the keycode > level, not scancode level. Therefore, you get weird key-up or > key-repeat events depending on the scan-order. > > The nicest fix, obviously, is to blacklist keys that are not > physically present on the keyboard. But I assume the keyboard reports Hmm, somebody could still load keymap with duplicate keycodes though... > > either key depending on the model (standard vs. European). Given that > this key is indeed special as we only have a single keycode for it, we > probably need some quirk like yours. I'd like to hear Dmitry's > comments on this, maybe he has had similar problems with non-HID > keyboards. Hmm, I do not think we have a good story for duplicate keycodes for drivers that send entire state as opposed to just changed bits. Thanks. -- Dmitry -- 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
