Re: [PATCH 0/2 v3] SGI RTC: add clocksource/clockevent driver and generic timer vector

From: Dimitri Sivanich
Date: Fri Nov 21 2008 - 12:17:20 EST


On Thu, Nov 20, 2008 at 05:44:22PM -0800, H. Peter Anvin wrote:
> Ingo Molnar wrote:
> > * Dimitri Sivanich <sivanich@xxxxxxx> wrote:
> >
> >> The following patches provide a driver for synchronized RTC
> >> clocksource and clockevents for SGI systems, as well as a generic
> >> timer system interrupt.
> >>
> >> With these patches, a module can be installed that registers the
> >> system-wide synchronized RTC clocksource and timers as both a
> >> clocksource and clockevents device running in high resolution mode.
> >>
> >> [PATCH 1/2 v3] SGI RTC: add clocksource driver
> >> [PATCH 2/2 v3] SGI RTC: add generic timer system interrupt
> >
> > Looks very clean and well-done to me.
> >
> > I had to take a good look at the rtc_timer_head->expires[] construct -
> > but i guess that's the best approach, as the max number of entries is
> > hard to judge at build time. (and we wont get any real limit
> > protection from gcc anyway)
> >
> > Thomas, any objections?
>
> I have *extremely* serious reservations about reserving even more
> hardware vectors for SGI only. This affects all systems, and quite
> frankly should not be necessary at all.
>
> The SGI UV people have pushed this at a number of points in the past,
> and we have told them to use an irqchip instead. This patch tries to
> allocate yet another reserved vector, instead.

I labeled the system vector as generic to indicate that this is available
to other platforms. See my other email to you for the reasons why I did
not use an irq instead.
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