Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.os.os2.programmer.misc > #1234

Re: Debugging presentation driver

Show all headers | View raw

On Fri, 30 Aug 2013 00:11:32 UTC, Paul Ratcliffe 
<abuse@orac12.clara34.co56.uk78> wrote:

> > The font support itself is working.  BUT... installing the driver has
> > a nasty side effect on the system.  Specifically, something seems to
> > go badly wrong with standard input in VIO sessions.  Whenever I run
> > CMD.EXE (windowed or fullscreen), a lengthy string of garbage appears
> > at the prompt (usually, at least) and the session immediately terminates.
> 
> I have had this effect before. Unfortunately I can't remember whether
> it was DOS or OS/2 command windows. Nor can I remember what the cause or
> solution was.
> 
> > The nature of the symptoms strongly suggest to me that something in my
> > driver is treading on internal PM memory somewhere.  The driver DLL is
> > loaded by Presentation Manager itself so presumably that gives it 
> > access to PM's privileged memory space.
> >
> > However, I'm at a loss to track this down.  I've gone through the code
> > to the best of my ability, and I really can't see any place where it
> > could be going wrong.
> 
> A vague memory is saying file handles to me. Can you try running Theseus
> and looking at the errant processes and see if anything looks odd,
> especially with regards to standard input (file handle 0)?

Good thinking.  I was just looking in Theseus with an eye to trying to see 
what memory was doing.  However, I noticed that three font files were 
listed as open, which should NOT happen.  All entrypoint functions are
supposed to close all open font file handles before returning. 

I've just gone through several attempts at improving this logic.  I've
just now managed to produce a build which does not SEEM to exhibit the
problem, and no longer shows any open font files in Theseus.  It's late
evening so proper testing will have to wait until tomorrow, but I'm 
keeping my fingers crossed.

(I think the change that did it was in the function that moves a font from 
the active cache to the idle list.  I was calling the Freetype API 
FT_Done_Face to clean up the font data.  It occurred to me that since this 
API expects to close the file itself, I should actually make sure it's OPEN 
first.  At any rate, that was the only significant change in the latest 
compile...)

Thanks!
-- 
Alex Taylor
http://www.altsan.org

Please take off hat when replying.

Back to comp.os.os2.programmer.misc | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Debugging presentation driver "Alex Taylor" <mail.me@reply.to.address> - 2013-08-29 01:30 +0000
  Re: Debugging presentation driver Andreas Buchinger <SendSpam@your.address> - 2013-08-29 20:38 +0200
    Re: Debugging presentation driver "Alex Taylor" <mail.me@reply.to.address> - 2013-08-29 19:12 +0000
      Re: Debugging presentation driver Paul Ratcliffe <abuse@orac12.clara34.co56.uk78> - 2013-08-30 00:07 +0000
        Re: Debugging presentation driver "Steven Levine" <steve53@nomail.earthlink.net> - 2013-08-30 01:08 -0500
          Re: Debugging presentation driver "Alex Taylor" <mail.me@reply.to.address> - 2013-08-30 15:31 +0000
            Re: Debugging presentation driver "Steven Levine" <steve53@nomail.earthlink.net> - 2013-08-30 13:26 -0500
          Re: Debugging presentation driver Paul Ratcliffe <abuse@orac12.clara34.co56.uk78> - 2013-08-30 23:55 +0000
  Re: Debugging presentation driver Paul Ratcliffe <abuse@orac12.clara34.co56.uk78> - 2013-08-30 00:11 +0000
    Re: Debugging presentation driver "Alex Taylor" <mail.me@reply.to.address> - 2013-08-30 03:07 +0000
      Re: Debugging presentation driver "Alex Taylor" <mail.me@reply.to.address> - 2013-08-30 15:34 +0000
        Re: Debugging presentation driver "Alex Taylor" <mail.me@reply.to.address> - 2013-08-30 22:10 +0000
  Re: Debugging presentation driver "A.D. Fundum" <what.ever@neverm.ind> - 2013-08-30 14:50 +0200
    Re: Debugging presentation driver "Alex Taylor" <mail.me@reply.to.address> - 2013-08-30 15:30 +0000
      Re: Debugging presentation driver "A.D. Fundum" <what.ever@neverm.ind> - 2013-08-30 19:30 +0200
      Re: Debugging presentation driver "Steven Levine" <steve53@nomail.earthlink.net> - 2013-08-30 13:29 -0500
        Re: Debugging presentation driver "A.D. Fundum" <what.ever@neverm.ind> - 2013-08-30 21:19 +0200

csiph-web