Re: unclean yanking out of device?

[Greg KH <greg@kroah.com>]

On Wed, Jan 14, 2004 at 05:08:49PM -0600, linas@austin.ibm.com wrote:
> On Wed, Jan 14, 2004 at 02:19:21PM -0800, Greg KH wrote:
> > On Wed, Jan 14, 2004 at 04:00:02PM -0600, linas@austin.ibm.com wrote:
> > > 
> > > What is supposed to happen if I just yank out a (network/scsi) device
> > > while it is being used, without calling any of the hotplug unregister
> > > remove etc. functions in advance?
> > 
> > Depends on the driver, device type, subsystem type, and most
> > importantly, the kernel version (2.2?, 2.4?, 2.6?)
> > 
> > This is better asked on the linux-kernel mailing list, with a specific
> > and detailed question, as you have asked a very broad one.
> 
> Sorry, this was intentionally a broad question; I'm hoping to hash
> out a broad answer here before I go lkml.
> 
> Let me rephrase:  I want to make 'appropriate' changes to the 2.6/2.7
> kernel, and some selected device drivers, so that a sysadmin can 
> stupidly yank out an *ordinary* PCI card (not a pcmcia) without doing 
> an orderly shutdown in advance.

Hahahaha... no, PCI drivers can not handle that.  See the PCI Hotplug
spec for why.  PCI drivers need to be told to shut down before removing
them.  And that will not change, sorry.

> More specifically, I have a whiz-bang PCI controller that will
> shut down a PCI slot when it is hit by a cosmic ray (data/address 
> parity error, other error, etc.).  I want to be able to "recover"
> that slot, (if its recoverable), and get things going again.

That pci controller needs to tell the OS that it is going to shut down
that pci slot.  Otherwise that pci controller violates the PCI spec.

Note, yes I know that cPCI controllers do this, that's a totally
different story... the os still needs to know before turning off a slot.

greg k-h


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