Date: Mon, 2 Jul 2007 15:12:37 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: Nate Lawson <nate@root.org> Cc: phk@phk.freebsd.dk, marck@rinet.ru, "M. Warner Losh" <imp@bsdimp.com>, current@freebsd.org Subject: Re: GEOM weirdness with SD flash reader? Message-ID: <20070702150825.L61395@fledge.watson.org> In-Reply-To: <4688947D.4040803@root.org> References: <54253.1183351841@critter.freebsd.dk> <4688878F.20406@root.org> <20070701.233153.-1343615328.imp@bsdimp.com> <4688947D.4040803@root.org>
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On Sun, 1 Jul 2007, Nate Lawson wrote:
>> : I disagree. Once scsi_da found the media, it would then somehow need to
>> : notify devd (i.e. to automount). If both functions are in devd, the
>> : loop becomes:
>> :
>> : while (1) {
>> : camcontrol tur mydev;
>> : if (found)
>> : notify_automount;
>> : break;
>> : sleep 3;
>> : }
>>
>> This doesn't belong in devd.
>>
>> Robert has patches to bring new geom entries into the realm of devd.
>
> URL?
This is from quite a long time ago, so likely needs massaging to apply.
http://www.watson.org/~robert/freebsd/geom_devctl.diff
The idea is straight forward: when a new geom device is discovered, we issue a
notification, which allows devd to respond to events above the newbus layer --
i.e., discover of an fdisk partition table, swap-backed md device, attachment
of a new software RAID layer, arrival of a volume by volume name, arrival of a
ZFS volume, etc.
A simultaneous discussion was going on regarding whether to notify about
ifnets directly, and my feeling was basically that since software components
care about the distinction between "em0" as a PCI device and "em" as a network
interface, and likewise between "ad0" as a disk device" and "ad0s1a" as a
partition. The other perspective was that newbus should grow to encapsulate
all these name spaces and services -- i.e., establish newbus nodes for md0,
lo0, etc, and use some combination of the attachment name space and object
types to handle this. I don't really mind what the end solution is, but I
found these patches quite useful locally :-).
Robert N M Watson
Computer Laboratory
University of Cambridge
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