Re: [SeaBIOS] Booting from USB thumbdrives, older drives boot, newer drives don't.

[Paolo Bonzini]

Il 04/03/2012 19:49, Kevin O'Connor ha scritto:
> > > The sg_modes command has a "-a" option to dump out all of the supported page codes
> > > it reports that none of the thumbdrives (tested 9) support page code = 4
> > > it reports that most of the thumbdrives (tested 9) support page code = 5
> > > it commented that page code 5 is obsolete
>
> Thanks Dave.  I appreciate your detailed analysis.
>
> The call to cdb_mode_sense_geom() was only recently added.  I'm
> inclined to just remove the call.  Paolo, is there a use case where
> having the "physical" chs info is important?  SeaBIOS should generate
> good "virtual" chs info regardless, and the underlying "physical" info
> is only exported in a couple of places.

MS-DOS doesn't boot if you do not export the physical chs.  I can remove
it, but it was the best testcase I had for SCSI support.

The simplest solution seems to be to look for page 4 support in page 0x3f.

Paolo