Hello, tech@
So I installed OpenBSD on old Compaq laptop and noticed that scrolling
with touchpad is not working. I started investigating to see why it
is the case and found out a few odd things in wscons(4) and pckbc(4)
drivers.
Basically, the laptop's touchpad lacks multifinger support (see dmesg
below), but nevertheless, wscons(4) sets it to two-finger mode, which
doesn't work, obviously. Initially, I thought about adding something
like mouse.tp.edgescroll to wsconsctl(8). I then found out that there
is already undocumented mouse.tp.param option, that can be used to
force the edgescroll mode by setting 67 (WSMOUSECFG_TWOFINGERSCROLL)
to 0 and 68 (WSMOUSECFG_EDGESCROLL) to 1, but I don't think it is
very convenient and readable.
Later I continued to investigate, why wscons(4) defaults to two-finger
mode and found that it does so by examining a field of a touchpad data
structure called 'contacts_max' [1], which, I assumed, represents
a number of maximum simultaneous touches. But when I grepped for
this name to see where this value is set, I found that it is set
in pckbc(4). It is done in a very simple way, so it sets it to 3
(well, actually SYNAPTICS_MAX_FINGERS, but it is defined to be 3
only there and nowhere else) if the device in question is a synaptics
touchpad (!) [2], even though the touchpad has a capabilities field
and it is recognized correctly (SYNAPTICS_CAP_MULTIFINGER is set
to 0 in my case). So I think a solution would be at least checking
SYNAPTIC_CAP_MULTIFINGER and setting contacts_max depending on that
(3 if true, 1 if false). Maybe it is a bodge, but it works.
Index: pms.c
===================================================================
RCS file: /cvs/src/sys/dev/pckbc/pms.c,v
retrieving revision 1.97
diff -u -p -r1.97 pms.c
--- pms.c 23 Jul 2022 05:55:16 -0000 1.97
+++ pms.c 18 Apr 2023 21:36:10 -0000
@@ -1075,7 +1075,10 @@ synaptics_get_hwinfo(struct pms_softc *s
hw->y_max = (max_coords ?
SYNAPTICS_Y_LIMIT(max_coords) : SYNAPTICS_YMAX_BEZEL);
- hw->contacts_max = SYNAPTICS_MAX_FINGERS;
+ if(syn->capabilities & SYNAPTICS_CAP_MULTIFINGER)
+ hw->contacts_max = SYNAPTICS_MAX_FINGERS;
+ else
+ hw->contacts_max = 1;
syn->sec_buttons = 0;
[1]: /sys/dev/wscons/wstpad.c:1573
[2]: /sys/dev/pckbc/psm.c:1078
Here are relevant lines from dmesg(8):
pms0 at pckbc0 (aux slot)
wsmouse0 at pms0 mux 0
pms0: Synaptics touchpad, firmware 6.5, 0x1c0b1 0xa00000 0x0 0xa04751 0x0
So I'm looking forward for comments on this. Has anybody experienced
something similar?
--
best regards,
la ninpre.
