Re: [RFC][PATCH -mm 3/3] PM: Disable _request_firmware before hibernation/suspend

From: Ray Lee
Date: Mon May 28 2007 - 16:51:27 EST


On 5/28/07, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
On Monday, 28 May 2007 17:55, Alan Stern wrote:
> 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.

Stupid question time. Wouldn't it just be easier to have
request_firmware() keep a copy of the firmware once it's been loaded?
We're not talking about a lot of memory that would be wasted, and that
way no drivers have to be changed.

Ray
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