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    SubjectRe: [patch 1/3] fastboot: Create a "asynchronous" initlevel
    On Sat, 19 Jul 2008 10:10:09 +0200
    Rene Herman <rene.herman@keyaccess.nl> wrote:

    > On 19-07-08 09:53, Rene Herman wrote:
    > > On 19-07-08 00:16, Arjan van de Ven wrote:
    > >
    > >> +static void __init do_initcalls(void)
    > >> +{
    > >> + initcall_t *call;
    > >> + static DECLARE_WORK(async_work, do_async_initcalls);
    > >> + int phase = 0; /* 0 = levels 0 - 6, 1 = level 6a, 2 = after
    > >> level 6a */
    > >> +
    > >> + async_init_wq = create_singlethread_workqueue("kasyncinit");
    > >> +
    > >> + for (call = __initcall_start; call < __initcall_end; call++) {
    > >> + if (phase == 0 && call >= __async_initcall_start) {
    > >> + phase = 1;
    > >> + queue_work(async_init_wq, &async_work);
    > >> + }
    > >> + if (phase == 1 && call >= __async_initcall_end)
    > >> + phase = 2;
    > >> + if (phase != 1)
    > >> + do_one_initcall(*call);
    > >> + }
    > >
    > > I'm not sure about this comment, being not very sure about the
    > > semantics of late_initcall but shouldn't late_initcall (level 7)
    > > wait for 6s to have completed?
    >
    > Following up on this myself -- see for example kernel/power/disk.c:
    > power_suspend(). It's a late intitcall so that, as it comments, "all
    > devices are discovered and initialized". However, your first followup
    > patch makes the USB HCI init async meaning that any USB storage
    > device might not be ready yet when it runs, no?


    good spotting/comment.

    you would have a valid point... if it weren't for the case where much
    of this actual "end device" probing is in various cases already
    asynchronous... what you do have found is a bug in the suspend code.
    Unless code does:
    /* wait for the known devices to complete their probing */
    while (driver_probe_done() != 0)
    msleep(100);
    (taken from init/do_mounts.c)

    ... the assertion in the comment that probing is done is absolutely
    false, with or without my patches.

    (Not that I want the suspend/resume code to call this, because that
    would make the boot even longer ;( )


    --
    If you want to reach me at my work email, use arjan@linux.intel.com
    For development, discussion and tips for power savings,
    visit http://www.lesswatts.org


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