[ECOS] from ISR to thread

[Patrick Doyle]

> ISR code:
> {
>   cyg_drv_isr_lock()
>   rbuf.putdata(hw.data)
>   cyg_drv_isr_unlock()
>
>   cyg_drv_interrupt_acknowledge()
>
>   return cyg_isr_call_dsr
> }
This one caught me by surprise.  Why would you have to an ISR lock/unlock
from within an ISR?  Were you just being extra careful in case some other
(higher priority?) ISR's happen to use the same ring buffer?

--wpd