shared memory

Mike Hauber m.hauber at mchsi.com
Thu Oct 28 08:25:59 PDT 2004


Greetings,

I have acquired a mo/bo with a built-in video adapter.  
Being that I have 768 megs of ram, I _know_ I have plenty 
of memory to allot to video.  BIOS doesn't pass this on to 
FreeBSD.

I have two choices for x.  I can use the VESA standard or I 
can use the S3 video driver (both come up fine, but theres 
quit a bit of chop when it comes to video processing 
regardless of which I use). 

I'm bringing up VESA from the kernal and it's giving it 16 
megs of ram.  Where can I read up on, or how can I increase 
this allotment?

As for the S3 video driver, do I allot the memory from the 
kernal or is this somehow set up from the x configuration 
file?  (I'm running x.org, although that probably shouldn't 
matter being that they pretty much seem the same at this 
point).

Applicable nfo as follows:

(from dmesg -a)

Timecounter "i8254"  frequency 1193182 Hz
CPU: AMD Athlon(tm) Processor (1202.73-MHz 686-class CPU)
  Origin = "AuthenticAMD"  Id = 0x644  Stepping = 4
  Features=0x183f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PA
T,PSE36,MMX,FXSR>
  AMD Features=0xc0440000<RSVD,AMIE,DSP,3DNow!>
real memory  = 788463616 (769984K bytes)
avail memory = 760496128 (742672K bytes)
Preloaded elf module "vesa.ko" at 0xc066d140.
...snip...
VESA: v3.0, 16384k memory, flags:0x1, mode table:0xc00c0e2a 
(c0000e2a)
VESA: S3 Incorporated. Savage4
...snip...
agp0: <VIA 82C8363 (Apollo KT133A) host to PCI bridge> mem 
0xd8000000-0xdbffffff
 at device 0.0 on pci0
pcib1: <VIA 8363 (Apollo KT133) PCI-PCI (AGP) bridge> at 
device 1.0 on pci0
pci1: <PCI bus> on pcib1
pci1: <S3 model 8a26 graphics accelerator> at 0.0 irq 9
...snip...
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 
0xa0000-0xbffff on isa0
...snip...


(from /sys/i386/conf/WIZARD, comments removed for cleaner 
reading)

cpu             I686_CPU
ident           WIZARD
maxusers        132
options         CPU_ATHLON_SSE_HACK
options         CPU_ENABLE_SSE
...snip...
options         USER_LDT
options         SHMALL=32768
options         SHMMAX=67108864
options         VESA
...snip...
device          sc0     at isa? flags 0x100
device          vga0    at isa?
device          agp
...snip...


From what I've read on it, I can tell you that I'm 
completely lost when it comes to shared memory (and reading 
more seems to confuse me more).  I simply don't understand 
how it works.  

Of course, I know that built in video is recommended against 
(regardless of what OS is running), but I'm sure there's a 
way to up the memory...  And I hope that theres a place 
that explains how it works in laymens terms?  :)

So far, I've re-read the manual on setting up x, for setting 
up video applications, various video app manuals, LINT, and 
many googles on shared memory.

Mayhaps there's a man page I'm missing that puts all this 
stuff in perspective?  If not, someone explain it so I can 
write one.  :)

Thanks.

Mike



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