On Fri, Aug 2, 2013 at 7:26 PM, Michael Schmitz <schmitzmic@xxxxxxxxx> wrote:
What is the cause of the problem exactly - the hsync handler changing the
IPL to block out further interrupts, whenever it is called for the first
time after interrupts are enabled? We could stop doing that on
multi-platform kernels (taking all hsync interrupts will be a performance
hit but not stop the system from working).
AFAICS, it's indeed the hsync handler blocking further interrupts on
multi-platform kernels.
So we could stop blocking further interrupts in multi platform kernels. How
much of a performance hit will this be on say a stock Falcon or TT?
That's 15000 - 30000 more interrupts per second.
We could ignore IPL2 when running on Atari (untested whitespace-damaged
patch):
[...]
or just ignore all priorities on all platforms, and consider interrupts
disabled
iff all priorities are disabled:
The former is safer but slower, the second is faster but will miss cases
where some interrupt priorities are disabled.
The safer but slower option (we can still use the fast version of it on
single platform kernels). We should test the faster at any rate to see
whether there are really cases where we miss disabled interrupts.
On single-platform kernels, ALLOWINT = ~0x500, and we can use the
current (fast) version.
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
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