device ada n/ in kernconf, how to omitt for hv_storvsc.ko

Ben Morrow ben at morrow.me.uk
Mon Mar 31 14:30:46 UTC 2014


Quoth "Chris H" <bsd-lists at bsdforge.com>:
> >
> > I'm experimenting with MS-Hyper-V and saw that as soon as hv_storvsc.ko
> > is loaded, an IDE hdd attaches as 'da' _and_ 'ada' (the former seems to
> > be called “FastIDE” on “synthetic storage driver” and gains efficiency
> > for HDD workloads).

Is this a problem? Can't you just ignore the one you don't want to use?

If nothing else, you could hide the device node using devfs.rules.

> > I'd prefere to disable 'ada' only (leaving cdrom via atapci->ATA_CAM->cd).
> > But I can't find the place where “device ada” gets defined for kernel
> > conf. “device ata” is in GENERIC, along with da, sa, scbus etc., but no
> > 'ada' ?!?. No trace of 'ada' in DEFAULTS either!?!
>
>  Off the top of my head, I /believe/ it's (ada) a part of the ahci
> implementation.

No, it works perfectly well without ahci (I'm using it with ataintel,
since the ICH7 in this box doesn't support AHCI).

It's compiled in with this line in sys/conf/files:

    cam/ata/ata_da.c                optional ada | da

which says 'include this file if either of "device ada" or "device da"
were requested'. So, I believe that if you want 'device da', you get
'device ada' as well, unless you edit that line to remove the '| da' and
make buildkernel. (I make no guarantee that this won't break things. I'm
not a kernel hacker.)

Ben



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