Re: [PATCH 1/4] scsi: Allow hosts to be flagged as hotpluggable

James Bottomley
2009-07-16T01:12:34Z

On Thu, 2009-07-16 at 00:43 +0100, Matthew Garrett wrote:
> Userspace may wish to make policy decisions based on whether a host
> supports device hotplug or not - for example, AHCI link power management
> disables hotplug, so may only be desirable on hotplug ports. Add
> support for marking hosts as hotpluggable in order to allow userspace to
> treat them appropriately.

OK, so I don't really understand what the hotplug flag means.

You seem to be setting it unconditionally on most sata HBAs. If it just
means "bus is hotpluggable", it should be set to 1 at initialisation and
the few non hot plug busses (like SPI) get to reset it.

However, by definition SATA (like SAS) is a hotplug bus ... why isn't it
set for some SATA controllers ... is it because the HBA itself does
something wrong when a hotplug event comes in?

James