From: Corey M. <mi...@ac...> - 2003-02-16 16:22:55
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Eric W. Biederman wrote: |Corey Minyard <cmi...@mv...> writes: | |>| |>|(So adding a special mode to the power management code may |>|be too much overhead. Besides, sometimes, you can just pull |>|a reset line, and don't have to do anything even remotely |>|related to power management.) |> |>True, I didn't mean the high-level power management code directly. But the |>PCI API defines a suspend operation that could take a special mode for this. | | |The generic device api has a shutdown method for this. And in the non panic |case we use it. Not a lot of devices have it implemented but it exists. | |And except that it doesn't have a restriction that it can't block is pretty |much what you want. That's a pretty big restriction. Plus, you can't claim spinlocks. The panic shutdown is different from an orderly shutdown. What the current shutdown does is probably not what you want. | |>Or maybe a new field in the PCI structure (and equivalent for other things, if |>there are any). But the suspend and resume operations should at least give |>a good idea where its needed and how to use it. | | |The API is already done... The API is not done for panics. There's no call that has the proper semantics. | | |We just don't trust the dying kernel enough to use it during a panic. I don't understand this. If you can't trust a dying kernel to properly shut down devices, how can you trust it to boot a new kernel? And (much worse) if you don't shut down the devices, how can you trust the new kernel to execute properly? I know there are levels of trust here, but I'd much rather have the kernel lockup during the reboot than have a chance of a new kernel booting that could behave incorrectly. In general, the chance of behaving incorrectly is MUCH worse than a sure lockup, especially in systems that must be reliable. - -Corey -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQE+T7rOIXnXXONXERcRAksfAJ9kVRD2S9OK5siBqAPMkbfi2iS2fgCeM3hw Fjp2LXiNEURU+HNrByOGVBQ= =5sxh -----END PGP SIGNATURE----- |