Date: Thu, 17 Jun 1999 14:54:52 -0600 (MDT) From: "Kenneth D. Merry" <ken@plutotech.com> To: tich@ma.ikos.com (Richard Cownie) Cc: dg@root.com (David Greenman), freebsd-current@FreeBSD.ORG Subject: Re: 4GB dram Message-ID: <199906172054.OAA89992@panzer.plutotech.com> In-Reply-To: <99061716084400.14101@par28.ma.ikos.com> from Richard Cownie at "Jun 17, 1999 03:55:11 pm"
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Richard Cownie wrote... > On Thu, 17 Jun 1999, David Greenman wrote: > > >I still can't get a machine with 4GB dram to work. When was the last > > >time anyone succeeded in running -CURRENT on a machine with 4GB dram ? > > >This was working for me with 19990421-CURRENT, it doesn't work in > > >19990604-CURRENT. Since support for 4GB dram is the only reason > > >I'm running -CURRENT rather than -STABLE, I would really like to know > > >when this might get fixed. > > > > You need to provide more information - specifically, what happens when you > > try? > > > > -DG > > boot: kernel.4G -v > Too many holes in the physical address space, giving up > Copyright (c) .... > Copyright (c) .... > > Fatal trap 12: page fault while in kernel mode > ... > > As I've noted earlier, the getmemsize() code doesn't appear very safe > w.r.t. 4GB limits. I tried rewriting to simplify this code and avoid > these problems - with the rewritten version I got further, but then > had a different crash later (but that could be due to a bug in my > rewrite). > > It's desperately painful to debug this, because as far as I know the > only way to get any kernel to boot is to power down the machine, physically > unplug one of the dimms, power up again, install new kernel, power down, > plug the dimm back in ... If I could fit the kernel on a floppy the > debugging cycle would be much quicker, but it seems too big for that. One thing I did once was to put a stripped-down kernel on a UFS-formatted floppy. (I took out everything I could to get it down to a size that would fit on a floppy) Then, from the boot loader, you can do something like: load disk0:/kernel boot Or something like that. You may have to set one of the boot loader variables to get the thing to boot off your hard disk. You should be able to strip a kernel down enough to fit it on a floppy, although you will have to specify some non-standard options. Two options that you'll want to use are: options SCSI_NO_SENSE_STRINGS options SCSI_NO_OP_STRINGS That will disable SCSI sense code and op code description strings. > Since the debugging is so painful, I would really like to find the latest > version that worked with 4GB, so that I can eyeball a minimal set of source > code changes. Ken -- Kenneth Merry ken@plutotech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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