Messages in this thread | | | Subject | Re: linux interrupt handling problem | Date | Tue, 9 Nov 1999 17:04:32 +0000 (GMT) | From | Alan Cox <> |
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> Alan> performance. On modern machines and things like the PC what you > Alan> say is very true but not on old m68k boxen > > I still don't see your point, if all non critical interrupts are > running with sti(), then your critical one (ie. serial in this case) > can interrupt any time. The serial handler is implemented so it runs > with all other interrupts disabled, ie. it never gets disturbed by > anyone. > > Where's the problem?
Tons of kernel code does
spin_lock_irqsave(...) Sit around spin_unlock_irqrestore(...)
On the 68K you really do want that to be spin_lock_irqsave_except_rtbits()
and you really do need that. It isnt even down to poor driver writing, the timing constraints on an 8530 on an old 68K box are horrible.
Right now a mac68k is pushing it to do 19200 baud in Linux but with rt hacks will do 115,200 and with irq path tidying should do 230,400
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