[Freemint-discuss] O_GLOBAL issues

[Miro K. <mir...@gm...>]

Hi,

I guess I'll post it here for better visibility. Basically I'm trying to
solve a bag if issues:

   - https://github.com/freemint/freemint/issues/143 (N.AES not working
   with /dev/console)
   - https://github.com/freemint/freemint/issues/173 (AES 4.1 stuck
   keyboard, mouse freeze and non-working double-click)
   - https://github.com/freemint/freemint/issues/378 (basically #173)

All of those are caused by removal of O_GLOBAL handling in
https://github.com/freemint/freemint/commit/9668d6797eaed45ffd9ee8e32770fb04e453f11a.
Helmut realised the same thing and even provided a fix for it:
https://mikro.naprvyraz.sk/mint/201511/msg00014.html so I have just
implemented it in my PR here: https://github.com/freemint/freemint/pull/379.

However, as it turns out, this fix solves most of the issues but not all of
them. Most notably the double-click issue and to some extent also the stuck
key issue (occasionally AES 4.1 still "overflows" with some stray keyboard
characters).

I can see the implementation of O_GLOBAL but I'm not 100% confident of its
purpose. To me it looks like a way to ensure that whatever file is opened
(even created in the past), it should be always handled as a file belonging
to the root process ("MiNT") and not others (AESSYS, NEWDESK, SCREEN etc).
That seems to have some unique properties like ensuring that no key is lost
due to task switching (or so, happy to be corrected here). The way it was
implemented was quite weird, basically any process handle >= 100 was
considered global, essentially limiting the number of open (non-global)
file handles to 99.

As this has been deprecated, I'm wondering: couldn't we just make one flag
in console.c (or dosfile.c) which would tell "this file handle is global
because it belongs to /dev/console" and treat it always as root process
handle?

Thorsten perhaps implied something similar here:
https://github.com/freemint/freemint/pull/379#issuecomment-2351411469 but I
want to double check. To me it seems like the best of both worlds,
/dev/console is always global and we don't need any kludges limiting the
number of open file descriptors.

-- 
http://mikro.atari.org