Re: [ECOS] Can excessive/intensive serial flow cause stack overflow?

[Alexandre <thekyz at gmail dot com>]

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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