Messages in this thread | | | From | TAMUKI Shoichi <> | Date | Fri, 11 Jun 2010 07:31:39 +0900 | Subject | Re: [PATCH v2] panic: keep blinking in spite of long spin timer mode |
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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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