Re: [PATCH] mmc: Add "ignore mmc pm notify" functionality

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On Tue, 12 Oct 2010, Dmitry Shmidt wrote:

> MMC_PM_KEEP_POWER is mostly related to mmc host controller - keeping 
> or not keeping power on suspend/resume.

It is not "mostly related", it is _totally_ related and actually its 
purpose for existing.

> MMC_PM_WAKE_SDIO_IRQ is not related to anything right now. Also in 
> most of the cases sdio irq can not be a wake source of the application 
> processor.

Why not?  I know about at least 2 host controllers which can be 
configured so a transition on DAT3 would wake up the host.

> Imagine your device is keeping connection during suspend. You got packet -
> wlan will wake application processor
> through external irq line and linux starts resume. You can not find wlan
> card again - it is too slow.

What?  I'm not following you anymore.

The Libertas firmware can be configured to filter incoming packets and 
only assert the IRQ signal only when a specific packet comes in, just 
like wake-on-LAN for Ethernet devices.

> Again, for mmc card it totally makes sense - mmc card is NOT an active
> device.

But MMC cards still have operating states.  You cannot simply write to 
them after a power disconnect, and leaving them powered on suspend is 
not very efficient either.

PS: common netiquette is not to top-post.


Nicolas
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