linux-kernel - Re: [GIT pull] irq updates for 4.13

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Date:   Tue, 11 Jul 2017 17:07:01 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Tony Lindgren <tony@...mide.com>
cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Sebastian Reichel <sebastian.reichel@...labora.co.uk>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ingo Molnar <mingo@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>, Pavel Machek <pavel@....cz>,
        Linus Walleij <linus.walleij@...aro.org>,
        Grygorii Strashko <grygorii.strashko@...com>
Subject: Re: [GIT pull] irq updates for 4.13

On Tue, 11 Jul 2017, Thomas Gleixner wrote:
> On Tue, 11 Jul 2017, Tony Lindgren wrote:
> > * Thomas Gleixner <tglx@...utronix.de> [170711 02:48]:
> > And "external abort on non-linefetch" means something is not clocked
> > in this case. The following alone makes things boot for me again, but I don't
> > quite follow what has now changed with the ordering.. Thomas, any ideas?
> 
> Ah. Now that makes sense.
> 
> Unpatched the ordering is:
> 
> 	  chip_bus_lock(desc);
> 	  irq_request_resources(desc);
> 
> Now the offending change reordered the calls. OMAP gpio has:
> 
>     omap_gpio_irq_bus_lock()
>        pm_runtime_get_sync(bank->chip.parent);
> 
> So that at least explains the error. So that omap gpio irq chip (ab)uses
> the bus_lock() callback to do runtime power management. Sigh, I did not
> expect that. Let me have a deeper look if that's OMAP only or whether this
> happens in other places as well.

So OMAP-GPIO is the only driver which abuses bus_lock/unlock() in that way
and gets surprised.

Thanks,

	tglx