RE: Hot PCI bus plugging

Bret Indrelee (bindrelee@sbs-cp.com)
Wed, 24 Nov 1999 11:22:14 -0600

Eric Lowe [mailto:elowe@myrile.madriver.k12.oh.us] wrote:
> I agree. I also think that modules that support hot plug
> devices should
> export an ioctl, callback routine, or such so that we can let
> the driver
> know when it's about to have a card yanked. Without changing
> the driver
> interface we don't gain much since we have to unload and reload the
> driver (not a pretty thing).
>
> The IRIX driver model would be nice for this-- the driver
> loads without
> attaching any devices. The kernel then invokes the driver's attach()
> routine for each device that the driver wants to claim. If devices
> are added, attach() is called at that time; if devices are removed,
> detach() is called then. The mechanism also supports partial
> unloading
> of unused modules (usually after 5 min) if the device has not been
> accessed recently.

I'm not familiar with the IRIX model, but thought that the Solaris model
handled most of the stuff in a reasonable way. In the past, my observation
has been all things IRIX tend to be a little clunky.

Is the IRIX model DDI/DKI?

The Solaris model is nice in that it also documents the race conditions that
you can get into between open, attach, and unload. They currently have
PCMCIA support. They have configuration files for each device.

I wouldn't want to copy all facets of the implementation. It is very
annoying that you have no way of controlling the instance number assigned to
a device. Since you usually use the instance number as your minor number,
this can cause some headaches.

-Bret

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Bret Indrelee, Engineer
SBS Technologies, Inc., Connectivity Products
1284 Corporate Center Drive, St. Paul MN 55121
Direct: (651) 905-4731
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E-mail: bindrelee@sbs-cp.com http://www.sbs.com
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