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Re: Can excessive/intensive serial flow cause stack overflow?
On Thu, Jul 3, 2008 at 5:39 PM, Andrew Lunn <andrew@lunn.ch> wrote:
> Duh... Didn't read the message correctly, so missed the obvious problem....
>
> I thought vector, then the problem is priority.....
>
> This is easy to explain. The actual serial driver is in
> /packages/devs/serial/generic/16x5x/current/src.
>
> It registers the interrupt handler with:
>
> cyg_drv_interrupt_create(ser_chan->int_num,
> CYG_IO_SERIAL_GENERIC_16X5X_INT_PRIORITY,
> (cyg_addrword_t)chan,
> pc_serial_ISR,
> pc_serial_DSR,
> &ser_chan->serial_interrupt_handle,
> &ser_chan->serial_interrupt);
>
> The priority is hard coded for all serial devices as 4.
>
> You can sort of override this. The same file says:
>
> #ifndef CYG_IO_SERIAL_GENERIC_16X5X_INT_PRIORITY
> # define CYG_IO_SERIAL_GENERIC_16X5X_INT_PRIORITY 4
> #endif
>
> but you don't appear to be able to override it per device, just for
> all devices. So i think you are not going to be able to benefit from
> vectored interrupts and will have to use a priority of 16. Or you need
> to have the serial driver to allow you to specify a priority level per
> device.
>
> Humm, actually, you could do something a little horrible like:
>
> #define CYG_IO_SERIAL_GENERIC_16X5X_INT_PRIORITY \
> (ser_chan->int_num == CYGNUM_HAL_INTERRUPT_UART0 ? 4 : 5)
>
> in arm_lpc2xxx_ser.inl
>
> Andrew
That does the trick.
The program stops there (after cyg_user_start(), some scheduler, clock
and thread work) :
************************************************************************************************
TRACE: intr.cxx [ 619] static void Cyg_Interrupt::disable_interrupts(
) {{enter
TRACE: intr.cxx [ 638] static void Cyg_Interrupt::disable_interrupts(
) }}return void
TRACE: intr.cxx [ 648] static void Cyg_Interrupt::enable_interrupts()
{{enter
TRACE: intr.cxx [ 664] static void Cyg_Interrupt::enable_interrupts()
}}return void
ASSERT FAIL: <1>hal_misc.c[155]exception_handler() Exception!!!
ASSERT FAIL: hal_misc.c [ 155] exception_handler()
Exception!!!
************************************************************************************************
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