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* Stopping mmc clock between transfers
@ 2011-05-24 18:42 Marc-André Hébert
  2011-05-25 15:54 ` Chris Ball
  0 siblings, 1 reply; 2+ messages in thread
From: Marc-André Hébert @ 2011-05-24 18:42 UTC (permalink / raw)
  To: linux-mmc

Hello,

We are using a OMAPL108 with 2.6.33 and noticed that the mmc clock
signal stays active when idle. This doesn't seem very power efficient
and we wondered if there was a reason for this. Before trying to fix
this on our side I had a few questions regarding this:
-Is this behavior the same in more recent versions?
-Was this designed to be this way?
-Would stopping the clock be a responsibility of the core (set_ios) or
the host controller (between requests)?

Regards
Marc

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: Stopping mmc clock between transfers
  2011-05-24 18:42 Stopping mmc clock between transfers Marc-André Hébert
@ 2011-05-25 15:54 ` Chris Ball
  0 siblings, 0 replies; 2+ messages in thread
From: Chris Ball @ 2011-05-25 15:54 UTC (permalink / raw)
  To: Marc-André Hébert; +Cc: linux-mmc

Hi Marc-André,

On Tue, May 24 2011, Marc-André Hébert wrote:
> We are using a OMAPL108 with 2.6.33 and noticed that the mmc clock
> signal stays active when idle. This doesn't seem very power efficient
> and we wondered if there was a reason for this. Before trying to fix
> this on our side I had a few questions regarding this:
> -Is this behavior the same in more recent versions?
> -Was this designed to be this way?
> -Would stopping the clock be a responsibility of the core (set_ios) or
> the host controller (between requests)?

Check out CONFIG_MMC_CLKGATE=y, introduced in 2.6.38.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2011-05-24 18:42 Stopping mmc clock between transfers Marc-André Hébert
2011-05-25 15:54 ` Chris Ball

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