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ISR's, DSR's and cyg_drv_interrupt_unmask()
- From: "Recker, John" <john_recker at hp dot com>
- To: "'ecos-discuss at sources dot redhat dot com'" <ecos-discuss at sources dot redhat dot com>
- Date: Fri, 29 Mar 2002 11:39:59 -0800
- Subject: [ECOS] ISR's, DSR's and cyg_drv_interrupt_unmask()
I've been playing with the serial
drivers for the EB40/AT91 recently
trying to improve its reliability.
One area that I think contributes to
the driver dropping characters is that
interrupts are not unmasked until both
the ISR & DSR have completed their tasks.
This is alot of instructions to process
on HW that requires that interrupt response
be within one character.
However, it seems that if I call
cyg_drv_interrupt_unmask() prior to
exiting the ISR routine, then the DSR
routine is never called. Is there a
way around this? It certainly is
straightforward to recode the DSR to
eliminate re-entrancy problems.
thanx,
jr
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