On Tue, Sep 20, 2022 at 12:54 PM Johnothan King <johnothanking@xxxxxxxxxxxxxx> wrote: > > Arne Wendt writes: > Cheap clone controllers may (falsely) report as having a user > calibration for the analog sticks in place, but return > wrong/impossible values for the actual calibration data. > In the present case at mine, the controller reports having a > user calibration in place and successfully executes the read > commands. The reported user calibration however is > min = center = max = 0. > > This pull request addresses problems of this kind by checking the > provided user calibration-data for plausibility (min < center < max) > and falling back to the default values if implausible. > > I'll note that I was experiencing a crash because of this bug when using > the GuliKit KingKong 2 controller. The crash manifests as a divide by > zero error in the kernel logs: > kernel: divide error: 0000 [#1] PREEMPT SMP NOPTI > > Changes in v2: > - Move the plausibility check to joycon_read_stick_calibration() and > have that function return -EINVAL if the check fails. > - In the plausibility check, change >= to ==. hid_field_extract() never > returns a negative value, so a scenario involving min > center or > center > max is impossible. > - To reduce code duplication, move the code for setting default > calibration values into a single function called > joycon_use_default_calibration(). > > Link: https://github.com/nicman23/dkms-hid-nintendo/pull/25 > Link: https://github.com/DanielOgorchock/linux/issues/36 > Co-authored-by: Arne Wendt <arne.wendt@xxxxxxx> > Signed-off-by: Johnothan King <johnothanking@xxxxxxxxxxxxxx> > --- > drivers/hid/hid-nintendo.c | 58 ++++++++++++++++++++++---------------- > 1 file changed, 33 insertions(+), 25 deletions(-) > Reviewed-by: Daniel J. Ogorchock <djogorchock@xxxxxxxxx> Thanks for the fix. This seems like a good way around invalid calibration data. -Daniel
