Re: [RFC] IRQ handlers run with some high-priority interrupts(not NMI) enabled on some platform

[Geert Uytterhoeven]

Hi Arnd,

On Thu, Feb 18, 2021 at 2:59 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
> On Thu, Feb 18, 2021 at 1:30 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> > The reason drivers/ide is doing that may be related to IDE hard drive
> > quirks.  The old WD Caviar drives didn't obey disabling the IDE interrupt
> > at the drive level.  On PC, that worked fine, as IRQs 14 and 15 weren't
> > shared with other devices.  On systems with shared interrupts, that
> > broke badly, and led to an interrupt storm.
>
> So presumably anyone that has one of those old drives will not be
> able to move to drivers/ata then? I see that drivers/ata doesn't do
> the transfers in interrupt mode, so it would seem to rely on masking
> at the device level.

I don't know.  This was an issue I debugged on a friend's Amiga in 1995
or so ;-)  All bad WD Caviars may have died in the meantime...

BTW, it wouldn't be the first time a drive quirk handling wasn't ported
from drivers/ide/ to drivers/ata/.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds