Re: New hal port + interrupts + rescheduling + call_pending_dsrs problem

["Davy Wouters" <davy dot wouters dot atos at gmail dot com>]

Hi Andrew,

I guess I got confused because i was thinking too much in the context
of the processor in stead of that of eCos.
The DSR mechanism has nothing to do with processor specific interrupt
handling but more with the eCos kernel internal stuff, correct?
In that case what is the exact role of the DSR in eCos? When to
implement one or not in a device driver?

I'm asking this because I thought that the DSR needed to be executed
after returning from the interrupt (reti or what ever), which is not
the case, in order to allow other interrupts
at this point. I thought that when combining ISR and DSR in one
interrupt handling of the processor, this would take too long and
deteriorate real-time behaviour?

Davy

On Fri, Jun 27, 2008 at 8:24 PM, Andrew Lunn <andrew@lunn.ch> wrote:
>> I assume a return from interrupt should be executed somewhere between
>> the execution of the isr/post_dsr and the call_pending_dsrs?
>
> Nope. If the scheduler is not locked, the DSR is called in the
> interrupt handler context. If the scheduler is locked, the DSR will be
> called when the scheduler is unlocked.
>
>> Is it correct that call_pending_dsrs should be executed only when
>> other interrupts are allowed again, in other words after return from
>> the interrupt?
>
> After returning from the interrupt handler which has been registered
> with eCos, but before the actual reti instruction, or what ever is
> used to return the processor from interrupt context back into normal
> context.
>
>> Sorry if my questions are a bit confusing, but i don't quite
>> understand the problems i'm having at this point (Crashes when having
>> a lot of communication
>> on my uart rx resulting in ASSERT_FAIL: <6>mutex.cxx[249]cyg_bool
>> Cyg_Mutex::lock() Locking mutex I already own)
>
> Is this crash in thread code? You are not allowed to use mutex, or any
> other blocking call in ISR or DSR context.
>
>      Andrew
>