Date: Thu, 04 Feb 2010 22:24:38 -0700 (MST) From: "M. Warner Losh" <imp@bsdimp.com> To: adrian.chadd@gmail.com Cc: freebsd-mips@freebsd.org Subject: Re: rspro board and mounting root from SD Message-ID: <20100204.222438.246077296855181113.imp@bsdimp.com> In-Reply-To: <d763ac661002042109o4522e5c1ia2eb51cf199bec75@mail.gmail.com> References: <d763ac661002042109o4522e5c1ia2eb51cf199bec75@mail.gmail.com>
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In message: <d763ac661002042109o4522e5c1ia2eb51cf199bec75@mail.gmail.com>
Adrian Chadd <adrian.chadd@gmail.com> writes:
: Howdy,
:
: I've been looking at using an SD card as a test root device but it
: unfortunately appears that device probing doesn't quite happen fast
: enough for the umass device to be enumerated.
:
: description:
:
: * system boots
: * usbus0 is created - root_mount_hold("usbus0") called
: * usbus0 is probed, and umass0 is found/createdcreated
: * umass0 probe begins
: * root_mount_rel() on usbus0 is called
: * nothing else is waiting, so VFS tries mounting the root device
:
: The SD probe/attach doesn't occur until -after- the root is mounted
: and the system begins.
:
: If I stick a root_mount_hold() call in umass_attach(), the umass
: device is given the opportunity to complete probe/attach but obviously
: then a lack of root_mount_rel() results in nothing completing.
Where did you put this?
: Any ideas? My knowledge of USB/CAM internals is currently
: non-existant. I couldn't find any particular function/callback which
: is called when the umass bus probe completes - as far as I can tell,
: attach kicks off some CAM messages which may eventually end up finding
: a device or not. I'm not sure of the "right" place to put the release;
: or whether I'm on the right track at all.
Maybe CAM should have something like this, but I'm not sure.
Warner
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