----- Original Message -----
From: "Paolo Bonzini" email@example.com To: "Kevin O'Connor" firstname.lastname@example.org Cc: "Dave Frodin" email@example.com, firstname.lastname@example.org Sent: Monday, March 5, 2012 1:17:08 AM Subject: Re: Booting from USB thumbdrives, older drives boot, newer drives don't.
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- it commented that page code 5 is obsolete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.
Except that none of the 12 devices I've tested support page 4. There's also a good chance that some of the devices could generate the stall on the page 3f request. That's what led us to thinking we should leave the page 4 query in and just add support to clear the stall.