Messages in this thread | | | Date | Thu, 3 Nov 2011 12:08:53 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH 2/3] scsi: add hooks for host runtime power management |
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On Thu, 3 Nov 2011, Tejun Heo wrote:
> Hello, > > On Thu, Nov 3, 2011 at 8:39 AM, Alan Stern <stern@rowland.harvard.edu> wrote: > >> I don't know. I haven't really thought about it but as it's currently > >> designed, I don't think it'll be possible to avoid going through EH to > >> put ATA ports into suspend mode. > > > > Why not? > > It's just how things are designed now. There's no reason why it's > fundamentally impossible but going around that would require some > amount of hackery or preferably re-design. Synchronization against > command processing, interrupts and all are built around EH.
Then it sounds like the best idea is something like what Ming proposed earlier: Have the error handler make some sort of test to determine whether it has been invoked for suspend/resume handling, and skip the runtime-PM calls on the host if it has.
This new test, whatever it is, should apply both to system suspend and runtime suspend. By the way, what would happen if a system suspend occurred while the ATA port was already runtime-suspended?
Alan Stern
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