Re: [PATCH v6 0/4] block layer runtime pm

On Tue, 8 Jan 2013, Aaron Lu wrote:

So this also reminds me that as long as CONFIG_PM_RUNTIME is selected,
the blk_pm_add/put/peek_request functions will be in the block IO path.
Shall we introduce a new config option to selectively build block
runtime PM functionality? something like CONFIG_BLK_PM_RUNTIME perhaps?

Just some condition checks in those functions, not sure if it is worth a
new config though. Please suggest, thanks.

I don't think it is needed.  The new routines will be very quick when 
blk_pm_runtime_init() hasn't been called, once you add back the checks 
for the queue's device.

Alan Stern