Bug#499833: [SOLVED] - chccwdev cannot set device offline in Lenny
On Wed, 3 Feb 2010 14:14:51 -0500 (EST), Frans Pop wrote:
> Because sysconfig-hardware gets triggered by udev when the kernel tells
> udev there's a new device...
> When you dynamically add hardware that way I guess it's a new device for
> the kernel, just like inserting/removing/reinserting a USB stick in a PC.
Hmm. I'm not so sure about that. If I DETACHED the device and then
LINKED it again, I would certainly agree with you. It's a "new"
device. But taking the device offline is not the equivalent of
a DETACH and LINK sequence. In fact, taking the device offline
is a *prerequisite* for a DETACH, if you want to do it cleanly.
The CP DETACH command and the CP LINK command each cause "machine-check"
conditions for "channel report pending", and are handled by the
kernel's machine-check interrupt handler. Varying the device offline
does no such thing. It's just an internal state change in the DASD driver.
I still think this is a bug. It may not be a bug in sysconfig-hardware.
It may be a bug in udev, I don't know. Nevertheless, I still
think there's a bug *somewhere*.
However, I do not wish to be contentious about this.
I know what caused it, and I know how to prevent it in the future.
And that's good enough for me. You have other matters
to attend to, I'm sure.