On Do, 2015-05-28 at 08:59 -0400, Gabriel L. Somlo wrote:
> > It is Very annoying to carry forward an outdatEd coNtroller with a mOdern
> > Machine type.
> >
> > Hence, let us not instantiate the FDC when all of the following apply:
> > - the machine type is pc-q35-2.4 or later,
> > - "-device isa-fdc" is not passed on the command line (nor in the config
> > file),
> > - no "-drive if=floppy,..." is requested.
>
> Don't forget the FDC0 entry in the ACPI DSDT !
No worries, everything is fine here.
> Right now, FDC0's _STA method returns 0x0F or 0x00, depending on the
> value of \_SB_.PCI0.ISA_.FDEN,
Yes.
> which is hard-coded to 1 (so 0x0F
> always, basically :) )
Yes on piix4.
On q35 FDEN maps to the floppy drive enable bit of the ich9 lpc. And
ich9_lpc_machine_ready() sets this (and other) enable bits.
/me double checks things.
Ok, in theory. In practice there seems to be something wrong. linux
kernel log on q35 (with floppy) yields this:
[root@fedora ~]# dmesg | grep pnp
pnp: PnP ACPI init
pnp 00:00: Plug and Play ACPI device, IDs PNP0b00 (active)
pnp 00:01: Plug and Play ACPI device, IDs PNP0303 (active)
pnp 00:02: Plug and Play ACPI device, IDs PNP0f13 (active)
pnp 00:03: Plug and Play ACPI device, IDs PNP0501 (active)
pnp: PnP ACPI: found 4 devices
Floppy (PNP0700) is not present. Hmm ...
Seems be be this:
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -494,7 +494,7 @@ static void ich9_lpc_machine_ready(Notifier *n, void
*opaque)
/* lpt */
pci_conf[0x82] |= 0x04;
}
- if (memory_region_present(io_as, 0x3f0)) {
+ if (memory_region_present(io_as, 0x3f2)) {
/* floppy */
pci_conf[0x82] |= 0x08;
}
Oh, and this ...
$ virsh qemu-monitor-command fedora-org-q35.base --hmp "info mtree" | grep fdc
00000000000003f1-00000000000003f5 (prio 0, RW): fdc
00000000000003f7-00000000000003f7 (prio 0, RW): fdc
... looks fishy too. Shouldn't that be 0x3f2-0x3f6 for the first range?
cheers,
Gerd
