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 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 | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/hid/hid-nintendo.c b/drivers/hid/hid-nintendo.c index 6028af3c3aae..7f287f6a75f5 100644 --- a/drivers/hid/hid-nintendo.c +++ b/drivers/hid/hid-nintendo.c @@ -793,7 +793,17 @@ static int joycon_request_calibration(struct joycon_ctlr *ctlr) &ctlr->left_stick_cal_x, &ctlr->left_stick_cal_y, true); - if (ret) { + + /* + * Check whether read succeeded and perform plausibility check + * for retrieved values. + */ + if (ret || + ctlr->left_stick_cal_x.min >= ctlr->left_stick_cal_x.center || + ctlr->left_stick_cal_x.center >= ctlr->left_stick_cal_x.max || + ctlr->left_stick_cal_y.min >= ctlr->left_stick_cal_y.center || + ctlr->left_stick_cal_y.center >= ctlr->left_stick_cal_y.max + ) { hid_warn(ctlr->hdev, "Failed to read left stick cal, using dflts; e=%d\n", ret); @@ -812,7 +822,17 @@ static int joycon_request_calibration(struct joycon_ctlr *ctlr) &ctlr->right_stick_cal_x, &ctlr->right_stick_cal_y, false); - if (ret) { + + /* + * Check whether read succeeded and perform plausibility check + * for retrieved values. + */ + if (ret || + ctlr->right_stick_cal_x.min >= ctlr->right_stick_cal_x.center || + ctlr->right_stick_cal_x.center >= ctlr->right_stick_cal_x.max || + ctlr->right_stick_cal_y.min >= ctlr->right_stick_cal_y.center || + ctlr->right_stick_cal_y.center >= ctlr->right_stick_cal_y.max + ) { hid_warn(ctlr->hdev, "Failed to read right stick cal, using dflts; e=%d\n", ret); -- 2.37.3
