Re: [PATCH v9 1/1] irqchip: imx-gpcv2: IMX GPCv2 driver for wakeup sources

From: Sudeep Holla
Date: Wed Aug 26 2015 - 04:52:27 EST

Hi Thomas,

On 25/08/15 20:26, Thomas Gleixner wrote:
On Tue, 25 Aug 2015, Sudeep Holla wrote:
On 25/08/15 15:54, Shenwei Wang wrote:
You don't really understand what happens after a driver calls
enable_irq_wake. In suspend state, even the interrupt
controller itself is powered off. How can you get the system up
again by just using a SKIP_SET_WAKE.

Sorry for that, let me try to understand aloud. So you have
irq_{un,}mask function that are called when interrupts are enabled and
disabled. So suppose you have 3 irqs that are enabled and only one of
then is set as wakeup source.

Now you call enable_irq_wake, you save that in wakeup_sources, fine.
Later when you enter suspend, you save all the 3 active irqs in
saved_irq_mask and over-write cpu2wakeup with wakeup_sources, right?

All fine, what I am saying is let irq-core know that you want to mask
the 2 non-wakeup irqs you have using MASK_ON_SUSPEND. So when
suspend_device_irqs is called in suspend path, that's done for you
automatically and the cpu2wakeup will have just 1 wakeup enabled which
is what you are doing in suspend callback, right ?

I missed that when I reviewed the patch. You are right, it can be

Now that it's already done for you, you need not do anything extra and
hence just set SKIP_SET_WAKE to do nothing.

Thanks for confirming this.

He still needs the set_wake function to capture the wake enabled
interrupts as they are handed over to the low level asm code via
imx_gpcv2_get_wakeup_source(). Though they could be read back from the
hw registers as well.

Correct, I have no objection on how it's saved/restored but was against
having 2 different masks and with the approach taken in this patch the
non-wakeup interrupts are enabled until syscore_suspend which is wrong.

There's whole lot of drivers blindly copy pasting this as theme which I
am going through and trying to clean up. I wanted to ensure no more such
additions happen meanwhile, so I am watching such patches closely.

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