Date: Fri, 25 Oct 1996 21:58:17 +0200 From: "Philippe Charnier" <charnier@xp11.frmug.org> To: hackers@FreeBSD.org Subject: 16MB -> 32MB and the boot fails Message-ID: <199610251958.VAA14625@xp11.frmug.org>
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Hello,
I moved this from questions to hackers. I added some printfs in the
kernel (and a dummy loop to see results) code to see why it fails on
my box if I don't add MAXMEM definition into the kernel.
My box is a 486dx50 ISA/VLB with AMI BIOS (1992). The bios detects the
memory and prints 32640K during memory test. I have BOUNCE_BUFFERS
enabled because of my AHA 1542CF.
>From /usr/src/sys/i386/i386/machdep.c(v 1.208):
void
init386(first)
int first;
{
[...]
pagesinbase = biosbasemem * 1024 / PAGE_SIZE;
pagesinext = biosextmem * 1024 / PAGE_SIZE;
I get pagesinbase = 160, pagesinext = 8000
[...]
if ((pagesinext > 3840) && (pagesinext < 4096))
pagesinext = 3840;
pagesinext is still 8000 here.
/*
* Maxmem isn't the "maximum memory", it's one larger than the
* highest page of the physical address space. It should be
* called something like "Maxphyspage".
*/
Maxmem = pagesinext + 0x100000/PAGE_SIZE;
Maxmem is 8256 here which seems to be more than my memory!!!
#ifdef MAXMEM
Maxmem = MAXMEM/4;
#endif
The working value I must set here is 8192. Maybe, there is something in the
code that _assumes_ Maxmem to be the maximum memory.
------ ------
Philippe Charnier charnier@lirmm.fr (smtp)
charnier@xp11.frmug.org (uucp)
``a PC not running FreeBSD is like a venusian with no tentacles''
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