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    SubjectRe: [PATCH v2] panic: keep blinking in spite of long spin timer mode
    Hello,

    On Thu, 10 Jun 2010 12:30:33 +1000 Anton Blanchard wrote:

    > > Please remind me why we're making this configurable at all. Can't we
    > > just hardwire the thing to 1Hz or something? Add an
    > > im_using_a_hypervisor boot option or something, if necessary?
    >
    > I agree. The panic_blink() interface is quite painful and I have no idea
    > why someone would want to configure the blink frequency of their keyboard
    > LED when panicing. Maybe they want to match it to the beat of their techno
    > music.

    That's cool. Joking aside, we might want to know which machine has
    paniced among two or more overcrowded machines. Maybe it is a good
    idea to change the blinking speed of each machine so as to distinguish
    whether the machine has paniced or not.

    > Since the keyboard LED default is a transition every 0.5s, why don't we just
    > remove i8042.panicblink and change all users (all 2 of them) to expect a 2 HZ
    > call rate? The hypervisor case should be fine with 0.5s mdelays, so we end up
    > removing that special case.

    If the speed of blinking is slow enough (i.e. panicblink<=5), both the
    native case and the hypervisor case should be fine, indeed. However,
    gta02_panic_blink(), one of panic_blink() users, expects a 10Hz call
    rate at the native case. IOW, it blinks at 5Hz (i.e. panicblink=36).
    I think that the desirable blinking speed is different according to
    devices.

    > I would have said 1 HZ, but it seems like the default was chosen to be
    > different to kdb:
    >
    > /*
    > * We expect frequency to be about 1/2s. KDB uses about 1s.
    > * Make sure they are different.
    > */
    >
    > No idea if that comment is still valid.

    That comment maybe still valid according to the following:

    On Sun, 30 May 2010 08:55:22 +0200 Andi Kleen wrote:

    > Changing the frequency is ok, the only requirement is that it is
    > visible and different from the frequency kdb uses.

    Regards,
    TAMUKI Shoichi


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