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| author | Michael Brown <mcb30@ipxe.org> | 2021-04-13 20:30:20 +0100 |
|---|---|---|
| committer | Michael Brown <mcb30@ipxe.org> | 2021-04-13 20:42:55 +0100 |
| commit | 8ca43ccbc1984d60e50711ea326ca59ac03985d2 (patch) | |
| tree | 36eec3856114d9aee452701e009b4b352873c267 | |
| parent | 3ae83222ce611afacd98419c0073aa98fb97f9e7 (diff) | |
| download | ipxe-8ca43ccbc1984d60e50711ea326ca59ac03985d2.zip ipxe-8ca43ccbc1984d60e50711ea326ca59ac03985d2.tar.gz ipxe-8ca43ccbc1984d60e50711ea326ca59ac03985d2.tar.bz2 | |
[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>
| -rw-r--r-- | src/arch/x86/interface/pcbios/int13.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/arch/x86/interface/pcbios/int13.c b/src/arch/x86/interface/pcbios/int13.c index 30530e1..d6c4d7e 100644 --- a/src/arch/x86/interface/pcbios/int13.c +++ b/src/arch/x86/interface/pcbios/int13.c @@ -678,10 +678,10 @@ static int int13_get_disk_type ( struct san_device *sandev, * @ret cx Extensions API support bitmap * @ret status Status code / API version */ -static int int13_extension_check ( struct san_device *sandev __unused, +static int int13_extension_check ( struct san_device *sandev, struct i386_all_regs *ix86 ) { - if ( ix86->regs.bx == 0x55aa ) { + if ( ( ix86->regs.bx == 0x55aa ) && ! int13_is_fdd ( sandev ) ) { DBGC2 ( sandev, "INT13 extensions installation check\n" ); ix86->regs.bx = 0xaa55; ix86->regs.cx = ( INT13_EXTENSION_LINEAR | |