On Wed, 29 Mar 2023 11:28:53 +0200, Takashi Iwai wrote: > > On Wed, 29 Mar 2023 11:22:18 +0200, > Hans de Goede wrote: > > > > Hi Takashi, > > > > On 3/29/23 10:16, Takashi Iwai wrote: > > > Hi, > > > > > > we've received a bug report about Thinkpad TrackPoint (ALPS DualPoint > > > Stick) on 6.2 kernel: > > > https://bugzilla.opensuse.org/show_bug.cgi?id=1209805 > > > > > > The device reports the wrong values as the movements, e.g. sometimes a > > > value such as 255, 254 or -255 is returned while usually it should be > > > a smaller value like -1 or 2. > > > > > > The evtest on 6.2.x kernel shows the wrong values like: > > > > > > Event: time 1680037542.898747, type 2 (EV_REL), code 0 (REL_X), value 255 > > > Event: time 1680037542.898747, -------------- SYN_REPORT ------------ > > > Event: time 1680037543.145196, type 2 (EV_REL), code 0 (REL_X), value 1 > > > Event: time 1680037543.145196, -------------- SYN_REPORT ------------ > > > Event: time 1680037543.175087, type 2 (EV_REL), code 1 (REL_Y), value -255 > > > Event: time 1680037543.175087, -------------- SYN_REPORT ------------ > > > Event: time 1680037543.185421, type 2 (EV_REL), code 0 (REL_X), value 1 > > > Event: time 1680037543.185421, type 2 (EV_REL), code 1 (REL_Y), value -255 > > > Event: time 1680037543.185421, -------------- SYN_REPORT ------------ > > > > > > while 6.1.x kernel shows the correct values like: > > > > > > Event: time 1680037386.318058, type 2 (EV_REL), code 0 (REL_X), value -1 > > > Event: time 1680037386.318058, type 2 (EV_REL), code 1 (REL_Y), value -1 > > > Event: time 1680037386.318058, -------------- SYN_REPORT ------------ > > > Event: time 1680037386.328087, type 2 (EV_REL), code 0 (REL_X), value -1 > > > Event: time 1680037386.328087, type 2 (EV_REL), code 1 (REL_Y), value -1 > > > Event: time 1680037386.328087, -------------- SYN_REPORT ------------ > > > Event: time 1680037386.338046, type 2 (EV_REL), code 0 (REL_X), value -1 > > > Event: time 1680037386.338046, type 2 (EV_REL), code 1 (REL_Y), value -2 > > > Event: time 1680037386.338046, -------------- SYN_REPORT ------------ > > > > > > I couldn't see any relevant changes in alps.c between those versions, > > > so this is likely a breakage in a lower layer. > > > > > > Could you guys take a look? > > > > I believe this is caused by the kernel now using -funsigned-char > > everywhere and this should be fixed by this commit: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git/commit/?h=for-linus&id=754ff5060daf5a1cf4474eff9b4edeb6c17ef7ab > > Ah, that makes sense! > > I'll build a test kernel with this fix and ask the reporter for > testing. And it's confirmed that the commit above fixes the problem indeed. thanks, Takashi
