Messages in this thread | | | Date | Thu, 4 Aug 2011 12:01:19 +0530 | From | viresh kumar <> | Subject | Re: [PATCH V2 08/20] dmaengine/amba-pl08x: support runtime PM |
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On 08/04/2011 11:06 AM, Koul, Vinod wrote: > On Thu, 2011-08-04 at 10:49 +0530, viresh kumar wrote: >> On 08/03/2011 06:09 PM, Russell King - ARM Linux wrote: >>> On Mon, Aug 01, 2011 at 03:07:18PM +0530, Viresh Kumar wrote: >> @@ -405,6 +406,7 @@ pl08x_get_phy_channel(struct pl08x_driver_data *pl08x, >> return NULL; >> } >> >> + pm_runtime_get_sync(&pl08x->adev->dev); > this should be ideally one of the first things you would do not last. > get_sync will ensure your .runtime_resume callback is called before it > returns (if its suspended) >> return ch; >> }
Until this point we are not touching the registers at all. And they will accessed after this point only.
>> + pm_runtime_put(&adev->dev); > _put is probe looks suspect, why do you need this here
To save power.
> as you are already setting the status as active, this _put will decrement your > usage count and possibly call your runtime_suspend
We set status as active, as amba/bus layer has enabled it before calling probe and it doesn't put it.
As DMA will not be used until get_phy_channel() is called, so we can save some energy here too. So i put it here.
-- viresh
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