From:	"A. Sinan Unur" <asu1 AT cornell DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Allegro 2.1 : Mach64 routines
Date:	Wed, 06 Nov 1996 13:27:58 -0500
Organization:	Cornell University
Lines:	42
Sender:	asu1 AT cornell DOT edu (Verified)
Message-ID:	<3280D8AE.3DB3@cornell.edu>
NNTP-Posting-Host:	cu-dialup-0007.cit.cornell.edu
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

i am trying to find a way for allegro tests and demos not to crash on a
computer with mach64 video card.

i just realized that choosing auto detect vs mach64 works fine. it also
reveals a possible reason for the crashes. in autodetect mode, both test
and demo do detect the card as a mach64 but say that it has 64K
granularity (i don't know exactly what granularity is). however, if you
check the sources (/src/ati.c) you can see:

GFX_DRIVER gfx_mach64 =
{
   "ATI mach64",
   "",
   mach64_init,
   NULL,
   mach64_scroll,
   _vga_vsync,
   _vga_set_pallete_range,
   0, 0, FALSE,
   0x10000,       /* 64k banks */
   0x8000,        /* 32k granularity */  <-------
   0
};

now, it seems to me like this could be the source of the crashes i
experience when i choose mach64 vs autodetect. as expected, naively
changing granularity to 64K does not improve the situation.

in all fairness to shawn, he does say at the beginning of ati.c that it
is incomplete.

any comments?

sinan.
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