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    SubjectRe: [RFC][PATCH -mm 3/3] PM: Disable _request_firmware before hibernation/suspend
    Date
    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.

    Greetings,
    Rafael
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