[Gta04-owner] [PATCH] omap-hsmmc: enable sdio interrupt to enhance wifi sdio performance

Andreas Kemnade andreas at kemnade.info
Fri Jun 15 08:01:06 CEST 2012


I found another interesting screw to play with:
fclk management. In 2.6.32 there were several patches to deal with that
so that for the wifi it is always enabled because of command timeout issues.
In 3.x fclk is hidden into pm_runtime.

The background of all this is (as far as I understand that now):
SDIO cards can generate interrupts. SDIO aware controllers can forward them
by generating an interrupt theirselves and setting a bit in their
interrupt registers.
So the controllers must be a bit awake for that and not only when the host
starts a data transfer. For host controllers which cannot forward the interrupts
from SDIO cards (or host drivers which do not implement that), there is a
polling mechanism in the kernel. The patch in the previous mail enables
that special interrupt.
I'm not totally sure about fclk management there. I hope improper fclk
management is the reason why I still need to do polling although
there are interrupts generated.

Andreas Kemnade
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