Re: SATA resume slowness, e1000 MSI warning

[ebiederm@xmission.com (Eric W. Biederman)]

"Kok, Auke" <auke-jan.h.kok@intel.com> writes:

> Eric W. Biederman wrote:
>
> [CHOP]
>
>> Below is an additional set of warnings that should help debug this.
>> The old code just got lucky that it triggered a warning when this happens.
>
>
> I'm trying this patch together with the other 2 that you sent out a few days
> ago. I'm seeing some minor issues with this and lots of bogus warnings as far as
> I can see.
>
> If I suspend/resume and unload e1000, then reinsert e1000.ko, I immediately hit
> the WARN_ON at `msi.c:516: WARN_ON(!hlist_empty(&dev->saved_cap_space));`
>
> I'm not sure that's useful debugging information. even though saved state exists
> the module has been removed, so you might want to purge the state table when the
> driver gets removed?
>
>
> anyway, back to testing.

Sorry I should have been clear.

With the last two patches I sent out:
pci: Repair pci_save/restore_state so we can restore one save many times.
msi: Safer state caching.

Those WARN_ON's are now totally bogus.  

In essence the WARN_ON's were testing to ensure pci_save_state and
pci_restore_state were paired.

The assumptions was that pci_restore_state would remove everything
from the list that pci_save_state placed on it.

When I reworked the code and removed the bogus pairing requirement it meant
that if we ever save state and have a pci-e or pci-x capability we will have
a state structure on the list until the kernel reboots. 

In summary:
pci_save_state and pci_restore_state were making a wrong assumption
about the world.  The WARN_ON patch tested to ensure the world matched
those functions.  When I fixed those functions to match the world the
WARN_ON's became completely bogus.

Eric