Rquestiing a power IRP
in [Device Drivers]
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From: Maxim S. Shatskih on 28 May 2010 09:59 > Is there a way to let the PNP subsystem know that we need a device to power > up or power down if we are not the power policy owner? No. >We need to make sure that a device is powered up before we ask the device something. Then you must be a PPO. Why is it hard? For most devices, the functional driver is also a PPO. -- Maxim S. Shatskih Windows DDK MVP maxim(a)storagecraft.com http://www.storagecraft.com
From: Pavel A. on 28 May 2010 12:21
"Maxim S. Shatskih" <maxim(a)storagecraft.com.no.spam> wrote in message news:udYcE4m$KHA.3880(a)TK2MSFTNGP04.phx.gbl... > Then you must be a PPO. > > Why is it hard? For most devices, the functional driver is also a PPO. In many interesting cases, it isn't. Example: the PPO for NDIS miniports is the ndis.sys. You want to put your USB netcard to sleep (SS), but cannot persuade ndis.sys to issue the power request. A solution proposed by Doron H. was to set a very short idle timeout. Wake up usually is trivial; when a request comes from top of the stack, the PPO just does the right thing. But again, the miniport or device may want to wake up for some internal reason, without ndis knows it... Regards, -- pa |