linux-kernel - Re: [PATCH 2/2] mfd: intel-lpss: Avoid resuming runtime-suspended lpss unnecessarily

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Message-ID: <1475048574.4635.1.camel@suse.com>
Date:   Wed, 28 Sep 2016 09:42:54 +0200
From:   Oliver Neukum <oneukum@...e.com>
To:     Chen Yu <yu.c.chen@...el.com>
Cc:     linux-pm@...r.kernel.org, "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
        Lee Jones <lee.jones@...aro.org>, linux-kernel@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH 2/2] mfd: intel-lpss: Avoid resuming runtime-suspended
 lpss unnecessarily

On Wed, 2016-09-28 at 11:28 +0800, Chen Yu wrote:
> So first try is to use pm_request_resume() instead, to make the
> runtime
> resume process asynchronously. Unfortunately the asynchronous runtime
> resume relies on pm_wq, which is freezed at early stage. So we choose
> another method, that is to avoid resuming runtime-suspended devices,
> if they are already runtime suspended. This is safe because for LPSS
> driver, the runtime suspend and system suspend are of the same
> hook - i.e., intel_lpss_suspend(). And moreover, this device is
> neither runtime wakeup source nor system wakeup source.

I agree with the reasoning but I don't see the specificity to LPSS.
Shouldn't this go into the core?

	Regards
		Oliver