commit 8ca43ccbc1984d60e50711ea326ca59ac03985d2
author Michael Brown <mcb30@ipxe.org> Tue Apr 13 20:30:20 2021 +0100
committer Michael Brown <mcb30@ipxe.org> Tue Apr 13 20:42:55 2021 +0100
tree 36eec3856114d9aee452701e009b4b352873c267
parent 3ae83222ce611afacd98419c0073aa98fb97f9e7

[int13] Do not report INT 13 extension support for emulated floppies

The INT 13 extensions provide a mechanism for accessing disks using
linear (LBA) rather than C/H/S addressing.  SAN protocols such as
iSCSI invariably support only linear addresses and so iPXE currently
provides LBA access to all SAN disks (with autodetection and emulation
of an appropriate geometry for C/H/S accesses).

Most BIOSes will not report support for INT 13 extensions for floppy
disk drives, and some operating systems may be confused by a floppy
drive that claims such support.

Minimise surprise by reporting the existence of support for INT 13
extensions only for non-floppy drive numbers.  Continue to provide
support for all drive numbers, to avoid breaking operating systems
that may unconditionally use the INT 13 extensions without first
checking for support.

Reported-by: Valdo Toost <vtoost@hot.ee>
Signed-off-by: Michael Brown <mcb30@ipxe.org>