On Mon, 10 Sep 2012, Shilimkar, Santosh wrote: > Thomas, > > On Mon, Sep 10, 2012 at 3:58 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote: > > On Mon, 10 Sep 2012, NeilBrown wrote: > >> > >> The IRQCHIP_MASK_ON_SUSPEND flag seems to be hard to use correctly, so either > >> I'm understanding it wrongly, or it could be made easier to use. > >> If the first case, I'm hoping that some improvement to documentation might > >> result. If the second, then maybe we can fix the code. > > ... > >> Is anyone able to give a definitive answer on this? Should > >> IRQCHIP_MASK_ON_SUSPEND be removed? > > > > The whole point of IRQCHIP_MASK_ON_SUSPEND is to deal with hardware > > designed by geniuses. > > > > Most SoCs have a way to mark the interrupts which serve as a wake up > > source as such. All other interrupts are magically "masked" on entry > > to suspend. > > > Just to support this, IRQCHIP_MASK_ON_SUSPEND does work with quite > a few ARM platforms too. OMAP already uses it in mainline and I have > seen patches for U500 and Tegra SOCs. Most of these usages are with > IRQ chips who doesn't have any driver run time PM supported and > the IRQ CHIP itself is shutdown when the CPU/CPU cluster gets > power down. So as far as functionality concerned with the flag, > it does what it suppose to do. > > > Now there is hardware which is missing such a control, so we need to > > mask the non wakeup interrupts right before going into suspend. > > > > That's what IRQCHIP_MASK_ON_SUSPEND does. Not more, not less. See > > commit d209a699a0b for more ugly details. > > > > You might be looking for a different functionality. Can you explain > > what you need? > > > Neil's email came from a discussion on the usage of this flag for > OMAP GPIO irqchip which I proposed. With the flag, when the > lazy check_irq routine is called, the GPIO driver is runtime suspended > and hence the late mask/unmask calls take abort(clocks are already gated). > GPIO IRQCHIP is secondary IRQCHIP connected to 1 interrupt line > per bank(32 GPIOs) to the primary interrupt controller IRQCHIP. So for this thing you need a IRQCHIP_MASK_BEFORE_SUSPEND variant? -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
