Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [RFC][PATCH -mm 3/3] PM: Disable _request_firmware before hibernation/suspend | Date | Mon, 28 May 2007 19:43:24 +0200 |
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On Monday, 28 May 2007 17:55, Alan Stern wrote: > On Sun, 27 May 2007, Rafael J. Wysocki wrote: > > > From: Rafael J. Wysocki <rjw@sisk.pl> > > > > Use a hibernation and suspend notifier to disable the firmware requesting > > mechanism before a hibernation/suspend and enable it after the operation. > > You're using the PM_PRE_FREEZE and PM_POST_THAW notifiers for both this > and the userspace helper change. Is it your intention that drivers > should continue to request these services but encounter an error if the > request occurs at the wrong time? Or do you expect drivers to use the > notifier chains to know when they shouldn't make any requests?
In fact, I'd like drivers to use notifiers to actually load the firmware into memory before hibernation/suspend. Namely, if there's PM_PRE_FREEZE, the driver calls request_firmware() from within the notifier and saves the firmware in memory for future use, if need be. Later, when PM_POST_THAW comes, the memory holding the firmware is released.
Unfortunately there are drivers that call request_firmware() directly from .resume() which blocks until timeout expires and fails anyway. I just wanted this to fail immediately, without waiting.
> In the second case you may have a problem, because there's no > specification about the order in which the notifiers are sent. The > service may get disabled before the driver learns it isn't available, > or the driver may think the service is once again available before it > gets enabled.
Yes.
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