Hi, Chris
2012/9/24 Chris Ball <cjb@xxxxxxxxxx>:
> Hi,
>
> On Fri, Sep 21 2012, Kevin Liu wrote:
>> Can latest code support sdio wakeup?
>
> Yes, it should work. OLPC has been using it in production with
> libertas_sdio for several years.
>
>> I see at last of sdhci_suspend_host, irq will be freed. But if the irq
>> is used for wakeup system like sdio wakeup irq? Then system can't be
>> woken up.
>
> free_irq() is just removing the handler while the stack is suspended, it
> isn't stopping your hardware from waking up the system. Your hardware
> needs to be programmed to wake the system if the SDIO IRQ fires; many
> SoCs will do this as long as the SDIO is in 1-bit data width mode (which
> doesn't require the card clock to be powered). We turn on 1-bit mode if
> MMC_PM_KEEP_POWER is set in host->pm_flags.
>
free_irq will also disable the interrupt line. Below is the comments and code:
The handler is removed and if the interrupt line is no longer in use
by any driver it is disabled.
/* If this was the last handler, shut down the IRQ line: */
if (!desc->action)
irq_shutdown(desc);
So if the irq is disabled, then system can't be woken up.
Thanks
Kevin
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