Re: [PATCH v7 4/4] sd: change to auto suspend mode

From: Alan Stern
Date: Mon Jan 28 2013 - 10:12:30 EST


On Mon, 28 Jan 2013, Aaron Lu wrote:

> > Someone just asked about the default autosuspend delay, and I realized
> > your patch series doesn't set one. Since we don't know the properties
> > of the disk drive at this point (or even whether the device is a disk
> > drive), the only safe course is to call
> >
> > pm_runtime_set_autosuspend_delay(&sdev->sdev_gendev, -1);
> >
> > before calling blk_pm_runtime_init(). Then autosuspends will be
> > prevented until userspace writes a non-negative value into the device's
> > control/autosuspend_delay_ms file.
>
> Shall we do it inside blk_pm_runtime_init? This way, we do not need to
> do it for every driver. And for drivers that do know a proper value for
> autosuspend delay, they can call pm_runtime_set_autosuspend_delay
> somewhere after blk_pm_runtime_init.

Yes, that seems like a good approach. Be sure to mention it in the
kerneldoc.

Alan Stern

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