Re: unable to install beta6 [amd64] on Dell 2850 with 4 GB RAM,workaround

From: Scott Long <scottl_at_FreeBSD.org>
Date: Thu, 30 Sep 2004 01:31:51 -0600
Claus Guttesen wrote:
>>You need to increase VM_KMEM_SIZE_MAX in your kernel
>>config, e.g.
>>options VM_KMEM_SIZE_MAX=536870912
> 
> 
> Did that, but it panicked, hand-transcribed screen:
> 
> vm_fault on nofault entry, addr : ffffffffb091d000
> KDB stack backtrace
> panic() at 0xffffffff8020bf17 = panic+0x2a7
> vm_fault() at 0xffffffff802f57b0 = vm_fault+0x1ce0
> trap_pfault() at 0xffffffff80330350 =
> trap_pfault+0x2a0
> alltraps_with_regs_pushed() at 0xffffffff8031c3fb =
> alltraps_with_regs_pushed+0x5
> amr_mapcmd() at 0xffffffff80184f34 = amr_mapcmd+0x114
> amr_start() at 0xffffffff801850e0 = amr_start+0x170
> amr_startio() at 0xffffffff801857ce = amr_startio+0x3e
> amr_submit_bio() at 0xffffffff80185bb0 =
> amr_submit_bio+0x20
> g_disk_start() at 0xffffffff801ed02a =
> g_disk_start+0xea
> g_io_schedule_down() at 0xffffffff801cf4ca =
> g_io_schedule_down+0xea
> g_down_procbody() at 0xffffffff801cfa28 =
> g_down_procbody+0x28
> fork_exit() at 0xffffffff801f17af = fork_exit+0x8f
> fork_trampoline() at 0xffffffff8031c5fe =
> fork_trampoline+0xe
> --- trap 0, rip = 0, rsp = 0xffffffffba13cd00, rbp = 0
> 
> Claus
> 

The AMR driver cannot handle >4GB of RAM.  Even though you only have 
4GB, your chipset is remapping part of it to the >4GB region.  The 
driver incorrectly interfaces with busdma and cannot handle this
scenario very well.  The panic is to be expected.  You can verify
this by setting the tunable 'hw.physmem' in the loader to some
value under 4GB to artifically limit the amount of RAM that the OS
sees.

Scott
Received on Thu Sep 30 2004 - 06:32:00 UTC

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