Re: What are you doing if the TX buffer overflows?

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 09/18/2012 08:50 PM, Wolfgang Grandegger wrote:
> On 09/18/2012 03:42 PM, Marc Kleine-Budde wrote:
>> On 09/18/2012 03:39 PM, Wolfgang Grandegger wrote:
>>> On 09/18/2012 03:00 PM, Marc Kleine-Budde wrote:
>>>> On 09/18/2012 02:49 PM, Wolfgang Grandegger wrote:
>>>> [...]
>>>>
>>>>>> We have several customers who asked how to abort pending TX messages,
>>>>>> too. Which involves:
>>>>>> a) clear the TX-queue in Linux
>>>>>> b) clear queue in hardware
>>>>>> c) abort currently transmitting CAN frame
>>>>>>
>>>>>> I think c) would be a usecase of its own, too.
>>>>>
>>>>> I think you need c) for b), at least for some controllers. These
>>>>
>>>> Yes, if it's a hardware limitation so be it. But if we design an
>>>> interface it should support "clear everything" (a+b+c), but also just
>>>> only c.
>>>
>>> Yes, that you be nice. The only portable "clear everything" (a+b+c) I
>>> see is "ifconfig down -> up". This also answers you other related mail.
>>>
>>> What do people really want/need and why? This is still not clear to me.
>>> More input would be nice.
>>
>> Heinz-Jürgen uses abort current TX Message on SJA1000, can you give us
>> more insight? I've talked to customers, e.g. they want to abort the
>> current frame if it takes "too long" to send it, because the frames CAN
>> id priority is too low.
> 
> What we could implement rather easily is a "tx-abort-last" or
> "tx-abort-all" netlink command. As this command does not make sense when
> more than one message is pending I'm in favor of "tx-abort-last".

I like to have both commands.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
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