Kurt Van Dijck wrote:
> On Mon, Feb 08, 2010 at 10:24:34AM +0100, Kurt Van Dijck wrote:
>> On Mon, Feb 08, 2010 at 10:12:12AM +0100, Wolfgang Grandegger wrote:
>>> Kurt Van Dijck wrote:
>>>> On Sun, Feb 07, 2010 at 06:25:39PM +0100, Wolfgang Grandegger wrote:
>>>>> christian pellegrin wrote:
>>>>>> On Sun, Feb 7, 2010 at 6:05 PM, Wolfgang Grandegger 
>>>>>> <[email protected]> wrote:
>>>>>>> christian pellegrin wrote:
>>>>>>> increase). Can you confirm that? Normal state changes are interrupt
>>>>>>> driver. So, if the hardware does not trigger an interrupt, we have a
>>>>>>> problem.
>>>>>> On the mcp251x we get an interrupt when we get back from error-warning
>>>>>> to error-active but I don't know if we have to send some kind of error
>>>>>> frame in this case. Now nothing is sent, I was worried if this is
>>>>>> right.
>>>>> Good question. I think we should send an error message for any state
>>>>> change also for passive->warning->active, which we currently do not
>>>>> handle by software. We speak about controller *problems* and there is
>>>>> currently no CAN_ERR_CRTL_ACTIVE. Well, that's another weak point :-(.
>>>>> This needs some more thoughts/discussion.
>>>> We had some discussion lately, but having an interrupt (and some message
>>>>    to userspace) seems like a non-optional requirement to me.

>>> I don't understand. What is "non-optional"? Currently we just report
>>> controller *problems*, meaning state changes
>>> active->warning->passive->bus-off.

This should answer your question below.

>> sorry for the confusion.
>> I meant: having an 'bus state change' interrupt seems a requirement to
>> me (therefore : non-optional, but it depends on CAN chip capabilities).
>> This (bus-state-change interrupt) is, IMO, more important than the bus
>> error interrupts.
>>
>> Therefore, I think that it may not be very good not sending anything
>> on the 'error-warning to error-active interrupt', as was mentioned
>> above.
>>
>> Implementing bus-error interrupts, but poor bus state change interrupts
>> requires the user to enable bus-error interrupts, and tracking the bus
>> state itself. I do not like that (But I did no mcp251x work either).
>>
>> I think we agree, but I didn't express my opinion very clear :-)
> 
> Looking back into the header file (error.h), I realize there is no
> option to report all bus-state changes yet, or I'm looking wrong.

No, see above.

Wolfgang.
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