New subject: [LinuxBIOS] EPIA-M VGA BIOS - X gives VIA(0): Bad V-BIOS checksum

23 Feb 2006


      Hello all,
my target: VIA EPIA-M 10000
Latest linuxbios (rev 2177)
I extracted the VIA VGA BIOS from the EPIA running official BIOS rev. 1.13.
However, my X server reports:
VIA(0): Bad V-BIOS checksum.
Everything before that looks good. Upon boot, I *do* get VGA output of FILO.
Would could be the cause? See below for details on what I did.
Regards,
Leon.
---<sidenote>---
As a sidenote, I think the HOWTO/EPIA-M is wrong about how to extract:
WRONG: dd if=/dev/mem of=/video.bios.bin \
WRONG: bs=1 count=65536 skip=790528
Note that 790528=0xC1000 and 65536=0x10000
/dev/mem must be read from 0xC000-0xD000 (VGA BIOS), whereas /proc/kcore 
must be read from
0xC1000-0xD1000 because kcore is an ELF 'view' to the memory, with a 
0x1000 ELF header at 0xC000.
What I did is extract from 0xC000-0xD000 as follows:
dd if=/dev/mem of=/113mem.bin skip=1536 count=128
(bs=512 by default)
---</sidenote>---
leon@nehemiah:/$ ls -ald /113mem.bin
-rw-r--r--  1 root root 65536 2006-02-23 03:57 /113mem.bin
leon@nehemiah:/$ hexdump -C /113mem.bin | head -n 10
00000000  55 aa 7d e9 26 7f 5e 1b  fa f9 f4 82 00 00 00 00  
|U.}.&.^.........|
00000010  00 00 00 00 00 00 00 00  44 00 d4 b0 c6 00 49 42  
|........D.....IB|
00000020  4d 20 43 4f 4d 50 41 54  49 42 4c 45 42 43 50 4f  |M 
COMPATIBLEBCPO|
00000030  53 54 00 00 18 00 30 34  2f 31 38 2f 30 33 01 15  
|ST....04/18/03..|
00000040  00 c0 c6 00 50 43 49 52  06 11 22 31 00 00 18 00  
|....PCIR.."1....|
00000050  00 00 00 03 40 00 51 01  00 80 00 00 00 01 20 20  
|....@.Q.......  |
00000060  20 56 49 41 20 54 65 63  2e 49 6e 63 2e 20 20 20  | VIA 
Tec.Inc.   |
00000070  20 20 20 20 20 20 20 20  20 56 45 52 2e 56 54 33  |         
VER.VT3|
00000080  31 32 33 20 20 20 20 01  15 01 12 56 49 41 20 20  |123    
....VIA  |
00000090  20 20 20 20 20 20 20 20  20 20 20 20 00 00 00 00  |            
....|
leon@nehemiah:/$ md5sum /113mem.bin
87017abc14c53e51a269fe59b5ba1508  /113mem.bin