Re: kern/55103: /dev/wsmouse returns EINVAL

[mlelstv%serpens.de@localhost (Michael van Elst)]

The following reply was made to PR kern/55103; it has been noted by GNATS.

From: mlelstv%serpens.de@localhost (Michael van Elst)
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/55103: /dev/wsmouse returns EINVAL
Date: Fri, 3 Apr 2020 06:05:08 -0000 (UTC)

 mrg%eterna.com.au@localhost (matthew green) writes:
 
 >i think the only real solution we have here is the sysctl
 >that changes the default, and having the depend on whether
 >there is a path for compat or not -- eg, if it is present,
 >then use it, or if it's possibly available (MODULAR) then
 >use it, but with no baked in compat or modules, the default
 >should be the only working method.
 
 I have prepared
 
 http://ftp.netbsd.org/pub/NetBSD/misc/mlelstv/wsevent.diff
 
 Default is now the new version but you can configure it with sysctl.
 This also means that you now must configure it to get the compat
 behaviour (in addition to building with COMPAT_50 or loading the
 module).
 
 I thought about chosing the default default version depending on
 build parameters.
 
 For the COMPAT_50 case that's easy, just set the default based
 on that parameter.
 
 For the modular case it's difficult because you don't know if the
 module will be loaded later.
 
 Just using the new version seems to be the least confusing mode
 because its very clear what you get and what you need to do for
 the extremly rare case that you need the old protocol version.
 
 You can add more complexity to the decision process (i.e. by
 loading the module earlier, even when not needed). But that
 contradicts why the compat code is separated into a module
 in the first place.
 
 So, if absolute compatibility with the old protocol version
 is wanted, it's probably easier, and safer, to just reintegrate
 the code back (it's a single function of about 20 lines) and
 drop the module.
 
 -- 
 -- 
                                 Michael van Elst
 Internet: mlelstv%serpens.de@localhost
                                 "A potential Snark may lurk in every tree."