Re: Mouse cursor jumping to the left of the screen with nativexorg

[Matthias Drochner <M.Drochner%fz-juelich.de@localhost>]

hubert%feyrer.de@localhost said:
> Not knowing any further implications of your patch

There is at least a runtime penalty: The FPU is
cleared once more for each signal handler call.

Also, there seems to be another problem, some race
condition which makes that the FPU context of the main
program is not restored correctly in rare cases, on
MP systems. I can reproduce this only if I bomb
a program with signals at a high rate, so it is not
too serious, but it shows that something is wrong
with FPU context handling or IPIs.

> Not so fast.. That handles i386, but it looks like amd64 needs a similar 
> treatment

The amd64 FPU code is almost identical. Can you try
the test program from the PR?

> if we're going to allow fp use in signal handlers we need to do it across 
> the board.

FP use in signal handlers is generally allowed. If it
causes problems, it should be fixed if possible.
(There is a known problem on i386 if COMPAT_16 is defined.
This is not easily fixed due to the strange way the backwards
compatible trampoline code is handled.)

best regards
Matthias




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