Re: Questions about masking interrupts when disabling interrupts

[Tony Lindgren <tony@atomide.com>]

* Kim Kyuwon <chammoru@gmail.com> [090108 03:27]:
> Thanks Tony very much for your reply!
> 
> On Wed, Jan 7, 2009 at 10:05 PM, Tony Lindgren <tony@atomide.com> wrote:
> > * 김규원 <chammoru@gmail.com> [090106 04:59]:
> >> Greetings,
> >>
> >> I'm enabling the Suspend-to-RAM state in our new OMAP3 Board.
> >> But I had some problems because of USB Interrupt.
> >>
> >> Although I disabled USB interrupt by disable_irq() function while
> >> entering the Suspend,
> >> M_IRQ_92 irq continuously wake up the OMAP3430 Processor.
> >>
> >> So, I fixed this problem as following patch.
> >>
> >> My Questions are:
> >> 1. Could anyone suggest the better solution for this problem?
> >
> > Maybe suspend the USΒ too? :)
> 
> I confirmed musb_suspend() function was invoked while entering Suspend-to-RAM
> state. musb_suspend() didn't disable USB interrupt, but only USB clock. Devices
> should be suspended with interrupts disabled
> (/Documenttation/power/devices.txt - 412line)
> 
> So I modified musb_suspend() to disable USB interrupt
> (I'm planning to send this patch very soon)
> I even wrote 0 to PM_WKEN_USBHOST[EN_USBHOST] bit. But our OMAP3430 board
> still have woken up by USB interrupt, because disable_irq() didn't mask the
> interrupt.

OK

> 
> >
> >> 2. If there is no better solution, can I be applied this patch to omap-tree?
> >
> > The patch looks OK to me, assuming the default enable calls unmask?
> >
> 
> Right, default_enable() function(kernel/irq/chip.c 222line) calls unmask

OK, pushing to l-o tree and adding to omap-fixes queue for mainline
kernel.

Tony

> 
> > Regards,
> >
> > Tony
> >
> >>
> >> Thank you!
> >>
> >> commit bbb49321b161e6a9ff2b73326d4012d8eb8bbf23
> >> Author: Kim Kyuwon <chammoru@gmail.com>
> >> Date:   Tue Jan 6 10:11:46 2009 +0900
> >>
> >>     ARM: OMAP3: Mask interrupts when disabling interrupts
> >>
> >>     By Ingo Molnar, interrupts are not masked by default.
> >>     (refer to 76d2160147f43f982dfe881404cfde9fd0a9da21)
> >>
> >>     But if interrupts are not masked, the processor can wake up while in
> >>     Suspend-to-RAM state by an external interrupt. For example, if an
> >> OMAP3 board
> >>     is connected to Host PC by USB and entered to Suspend-to-RAM
> >> state, it wake up
> >>     automatically by M_IRQ_92. The disable_irq() function can't disable the
> >>     interrupt in H/W level, So I modified arch/arm/mach-omap2/irq.c
> >>
> >>     Signed-off-by: Kim Kyuwon <chammoru@gmail.com>
> >>
> >> diff --git a/arch/arm/mach-omap2/irq.c b/arch/arm/mach-omap2/irq.c
> >> index 110acb9..b44dcae 100644
> >> --- a/arch/arm/mach-omap2/irq.c
> >> +++ b/arch/arm/mach-omap2/irq.c
> >> @@ -123,6 +123,11 @@ static void omap_unmask_irq(unsigned int irq)
> >>       intc_bank_write_reg(1 << irq, &irq_banks[0], INTC_MIR_CLEAR0 + offset);
> >>  }
> >>
> >> +static void omap_disable_irq(unsigned int irq)
> >> +{
> >> +     omap_mask_irq(irq);
> >> +}
> >> +
> >>  static void omap_mask_ack_irq(unsigned int irq)
> >>  {
> >>       omap_mask_irq(irq);
> >> @@ -134,6 +139,7 @@ static struct irq_chip omap_irq_chip = {
> >>       .ack    = omap_mask_ack_irq,
> >>       .mask   = omap_mask_irq,
> >>       .unmask = omap_unmask_irq,
> >> +     .disable = omap_disable_irq,
> >>  };
> >>
> >>  static void __init omap_irq_bank_init_one(struct omap_irq_bank *bank)
> >> --
> >> Kim Kyuwon
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
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> >
> 
> Regards,
> -- 
> Kim Kyuwon
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