Re: [PATCH 1/3] Input: Fixed ABS_MT_TOUCH_MINOR scale factor in BCM5974 multitouch driver
From: Henrik Rydberg <hidden>
Date: 2013-11-21 09:30:43
Also in:
lkml
From: Henrik Rydberg <hidden>
Date: 2013-11-21 09:30:43
Also in:
lkml
Hi Friedrich,
On wellspring3 devices ABS_MT_TOUCH_MINOR was sometimes reported bigger than ABS_MT_TOUCH_MAJOR. This is fixed by rescaling ABS_MT_TOUCH_MINOR by a factor of 0.85 instead of 2. Excessive tapping on the trackpad shows this to be the right value. Circular touches should now lead to values for ABS_MT_TOUCH_MAJOR and ABS_MT_TOUCH_MINOR that are similar, with ABS_MT_TOUCH_MINOR never greater than ABS_MT_TOUCH_MAJOR. --- drivers/input/mouse/bcm5974.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-)
The major/minor scales are following the aspect ratio of the device, and as such it could happen that minor > major. Most userland drivers do not use the finger width limits, which are estimates, but only the device axes limit, which are accurate. Also, we cannot have floats in the kernel. I would consider a patch which tries to make the finger widths more accurate, but all in all, I think this problem is best solved in userland. Thanks, Henrik