Re: sci spurious irq on sh7203

[Federico Fuga <fuga@studiofuga.com>]

Hi Magnus,

thank you very much for your response!
As you suggested, I made both test - disabling the earlyprintk on the 2.6.37 [nothing changes] and trying the same test with the latest, git version. In the this case, after applying all changes to support my board (this means only some change to the arch/sh/boards/mach-rsk/devices-rsk7203.c, arch/sh/boards/mach-rsk/setup.c) the system doesn't output anything on the serial console, neither with nor without the earlyprintk option.
I'am stuck :-)
I double checked all my modifications, but there's nothing related to serial port sci0. And in my old (2.6.37) sh_sci.c there is no changes other than some debug message...
Any idea?

Thank you!

Regards,


Federico Fuga






Il giorno 02/mag/2011, alle ore 22.48, Magnus Damm ha scritto:

> Hi Federico,
> 
> On Tue, May 3, 2011 at 3:11 AM, Federico Fuga <fuga@studiofuga.com> wrote:
>> Hi All,
>> 
>> I am working on a sh7203 based board, running the linux-sh kernel 2.6.37 [3c0eee3fe6a3a1c745379547c7e7c904aa64f6d5]
>> I am experiencing a bug when using the sci0 as a console.
>> The serial port is working as expected, except when more than a certain number of characters are sent to the console; in this case, the kernels traps many spurious interrupts that triggers the __report_bad_irq() function and disables the IRQ vector 192.
>> I append a snapshot of the console output.
>> As you can see, I modified some kernel sources to output the status of some register - also not related to SCI.
>> I modified the sh_sci.c source to trigger an output of the irq registers when no irq routine is serviced - basically a flag that change state when sci_tx_interrupt or similar function are called from inside sci_mpxed_interrupt.
>> So I noted that the error is triggered when
>> 
>> ssr_status\0000060
>> scr_status\0000078
>> err_enabled\0000040
>> 
>> The strange thing is that the irq is triggered for TEND flag and TX FIFO Empty even if TIE is disabled.
>> I was investigating both tx and rx interrupt routines, but I see nothing strange happening. But it seems something related to Receiving too many characters (a stream of 15 bytes do not triggers the problem; 16+ bytes almost always triggers the problem), since Sending seems to work fine.
>> I also tried to update sh-sci.c/h and some other header file (in arch/... and include/linux/...) to the latest version, and compile, but the problem persists.
>> Actually I cannot test any other serial port for this problem, but I hope I can make this test soon.
>> Thank you in advance.
> 
> As usual with these things, please try to test on latest upstream if
> possible. Your issue may be solved already and if so is a matter of
> backporting.
> 
> I don't recall any recent sh7203 serial fixes though. You may want to
> try to test without earlyprintk. From your description it sounds like
> your issue may be related to TX errors (overrun), perhaps the TX error
> interrupt is enabled even though TIE is disabled?
> 
> Thanks,
> 
> / magnus