Input driver on 1.15.1 vs. 1.19.6

[Software Orchestration]

  Alan Coopersmith <alan.coopersmith at oracle.com> wrote: > I have no idea who decided what releases to list there as supported, but X.Org
> certainly isn't supporting all those releases upstream - though some downstream
> distros may be doing so. X.Org itself is mainly maintaining the 1.20 series now:
> https://gitlab.freedesktop.org/xorg/xserver/-/branches

I figured you were on this list...thanks for replying.
My question is first trying to understand what I need to get this working on Ubuntu 18.04. Currently the Xorg server is 1.19.6 and I don't see that changing until 20.04. They will still have 1 more year on 18.04 as it's a 5 year LTS I believe.
First I'm just trying to understand if interfaces changed, if legacy works at all, or what the differences are so I can isolate the problem and fix it.
If an input driver was brought up to 1.19.x, would it be likely to run on 1.20.x?
I think I could get 1.20 on Ubuntu 19.08, do you know if that's the case?

> There certainly have been driver API/ABI updates between the two:
> https://www.x.org/wiki/XorgModuleABIVersions/
I saw in 1.16.x there was quite a bit of input changes, but wasn't sure how the APIs are supported.
There seems to be a fairly large grey area.
On top of all that, the was hacked together from another serial device, so as you might imagine it's a pretty big mess...but the good thing is there's only about 1000 LOC for the current driver.
I'm trying to figure out if I might be better off starting off with a current serial input device as a template and merge their code to get a working driver on 18.04. 

> > The code uses xf86ReadSerial() and xf86WriteSerial().
>
> Doesn't look like there's been a whole lot of change there in recent years:
> https://gitlab.freedesktop.org/xorg/xserver/commits/master/hw/xfree86/os-support/shared/posix_tty.c

That's good, maybe my chance is pretty good on 18.04.

> Examples of input device drivers for Xorg?
> 
> https://gitlab.freedesktop.org/xorg/driver?filter=input> ...
> XFREE86_V3 code is almost 20 years out of date now, while XFREE86_V4 code would
> be closer to 15 years out of date.
Thanks for that link, looks like the xf86-input-libinput might be good for me to look at.
I wish I wasn't doing this, but I really needed the work...so...I'd like to try and solve this for my client. Running on an old Atom processor that is at least 10+ years old, limited on memory, etc...I've seen this movie a number of times over the years...it's kind of like a rerun...:-/

Alan
  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.x.org/archives/xorg/attachments/20191010/2528a32a/attachment-0001.html>