Re: [PATCH 2.6.10-rc1 0/4] driver-model: manual device attach

From: Tejun Heo
Date: Fri Nov 05 2004 - 01:33:52 EST


On Fri, Nov 05, 2004 at 12:02:57AM -0500, Dmitry Torokhov wrote:
> I think that my bind)mode patches which allow to control binding through
> sysfs on pre-device and per-driver base should suffice here. I really doubt
> that anybody would want to keep autoattach disabled and do all matching
> manually ;). Besides having per-driver attribute allows drivers authors
> control binding.

Think about extending hotplug to cover all device bindings. It will
kick in very early in the booting process (maybe in the initrd image)
and names/binds every device on the device with appropriate arguments
as user requested. I was thinking about usages like that when I was
making the sysctl node. Maybe I was going too far. :-)

> Do we really need 2 or even 3 files ("attach", "detach" and "rescan")?
> Given that you really can't (at least not yet) do all there operations
> for all buses from the core that woudl require 3 per-bus callbacks.
> I think reserving special values such as "none" or "detach" and "rescan"
> shoudl work just fine and also willallow extending supported operations
> on per-bus basis. For example serio bus supports "reconnect" option which
> tries to re-initialize device if something happened to it. It does not
> want to do rescan as that would generate new input devices while it is
> much more convenient to re-use old ones.

How about making the command format "CMD ARGS" rather than
"{CMD|DRIVERNAME}" i.e.

not

# echo e100 > drvctl
# echo detach > drvctl

but

# echo attach e100 > drvctl
# echo detach > drvctl

But, I don't know. It now just seems too much like a proc node.

> I disagree. Here you working with particular device. You are not saying
> "from now on I want e100 to bind all my 5 new network cards that happen
> to have id XXXX:YYYY". Instead you are saying "I want to bind e100 driver
> to this card residing at /sys/bus/pci/0000.....". In other word it is
> operation on particular device and should be done by manipulating device
> attribute.

I kind of agree with you but I think either way is fine.

Thanks.

--
tejun

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