[flashrom] testing DELL Dimension 4100

[Stefan Tauner]

On Sat, 29 Dec 2012 16:18:15 +0000 (GMT)
Bertho Grandpied <y31415926536 at yahoo.fr> wrote:

> Testing Dell Dimension 4100 : Pentium III and Intel 815 (82815 + 82801BA, ICH2) based desktop machine from ca yr 2000.
> 
> This chipset should be supported IIUC, but flash chip is not detected :(
> 
> Flashrom was run under MS-DOS (log appended) - notice how I had to specify the "not-a-laptop" override because of insufficient DMI tables. Please notice also the "warning" about being unable to set Bios Control at 0x4e : thus the question arises, is that Intel chipset variant supported or is it not ?

hi,

(intel) chipsets can be configured by the bios in a lot of ways and
since some configuration options are directly targeted at restricting
flash chip access, chipset support as defined by flashrom/us does not
necessarily mean that flashrom can actually access the flash chip
freely. most of the time this does only affect writing.

> WARNING: Setting Bios Control at 0x4e from 0x02 to 0x03 on ICH2 failed.
> New value is 0x02.
> FAILED!

this is telling us that we failed to set bit 0 of BIOS_CNTL. this bit
is named "BIOS Write Enable"...
the reason why we failed to set it, is that bit 1 is also set, which
indicates that the BIOS will be called whenever one sets bit 0. and
obviously in this machine (and usually always) the BIOS then just
unsets the bit again... no flash writes possible without telling the
BIOS to stop this behavior... which is not documented. Dell has been
known for doing this for a long time.

Since this system is so old, I wont add it to our list of (un)supported 
hardware...

This does however not explain why we do not find a flash chip. Most
probably it is not supported yet. The EC (SMSC) might be involved too.
If you care please tell us the markings on the flash chip. Support for
reads should be easy to add, but writes won't happen at least on that
board...
-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner