Bug#927091: linux-image-5.0.0-trunk-amd64: Broken scrollwheel after upgrade
Hi,
I bisected the kernel to the following commit:
2dc702c991e3774af9d7ce410eef410ca9e2357e is the first bad commit
commit 2dc702c991e3774af9d7ce410eef410ca9e2357e
Author: Peter Hutterer <peter.hutterer@who-t.net>
Date: Wed Dec 5 10:42:24 2018 +1000
HID: input: use the Resolution Multiplier for high-resolution scrolling
Windows uses a magic number of 120 for a wheel click. High-resolution
scroll wheels are supposed to use a fraction of 120 to signal smaller
scroll steps. This is implemented by the Resolution Multiplier in the
device itself.
If the multiplier is present in the report descriptor, set it to the
logical max and then use the resolution multiplier to calculate the
high-resolution events. This is the recommendation by Microsoft, see
http://msdn.microsoft.com/en-us/windows/hardware/gg487477.aspx
Note that all mice encountered so far have a logical min/max of 0/1, so
it's a binary "yes or no" to high-res scrolling anyway.
To make userspace simpler, always enable the REL_WHEEL_HI_RES bit. Where
the device doesn't support high-resolution scrolling, the value for the
high-res data will simply be a multiple of 120 every time. For
userspace,
if REL_WHEEL_HI_RES is available that is the one to be used.
Potential side-effect: a device with a Resolution Multiplier applying to
other Input items will have those items set to the logical max as well.
This cannot easily be worked around but it is doubtful such devices
exist.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Verified-by: Harry Cutts <hcutts@chromium.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
:040000 040000 fc4c9b48f3723ef6a8f36b768308bb3c99c9f882
475d4548b75765df6447e43992b07259b181f515 M drivers
:040000 040000 dc356f23227a874721e6688445fc2b90f726e2a7
2190e33e4ad1bcaff0b35dc03194f29fbd9493c6 M include
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