I2c producing crazy console messages [[Re: insanely-high interrupt rates -- PARTIAL resolution (Pi2)]]

[Karl Denninger]

On 4/18/2019 17:57, Ian Lepore wrote:
> On Thu, 2019-04-18 at 16:51 -0500, Karl Denninger wrote:
>> Up until 12.0 this code both worked and did *not* generate complaints
>> about unhandled interrupts.  It still runs fine and returns valid
>> data
>> BUT if there are any analog endpoints actually on the bus that the
>> code
>> can read then it generates a lot of these:
>>
>> local_intc0: Spurious interrupt detected
>> local_intc0: Spurious interrupt detected
>> intc0: Spurious interrupt detected
>>
>> .....
>>
>> If I do not connect the I2c device then there are no messages.  If I
>> stop the code that is running (e.g. no accesses to the i2c bus) then
>> the
>> messages stop as well, so it's not something that happens but remains
>> active after the code halts; it's happening on the actual accesses to
>> the bus from those ioctl's.
> Hmm, another interesting question occurred to me:  Can you tell whether
> you are getting multiple spurious interrupt messages per single
> transfer your code does, or is it one per transfer, or more
> intermittent, like not on every transfer?
>
> -- Ian

It logs the message on "many" accesses, but not all.

The code scans each of the declared analogs once per second.  There are
two inputs defined on this unit right now, so if it was on every access
there would be two messages per second logged, and there isn't; nor is
it "one per cluster" of accesses.  I removed the reset and restarted the
code and this is the frequency of log entries I'm getting, which implies
frequent and random, but much less than 1:1.

Apr 18 20:22:25 Pool-MCP kernel: intc0: Spurious interrupt detected
Apr 18 20:22:26 Pool-MCP kernel: local_intc0: Spurious interrupt detected
Apr 18 20:22:27 Pool-MCP kernel: intc0: Spurious interrupt detected
Apr 18 20:22:33 Pool-MCP kernel: local_intc0: Spurious interrupt detected
Apr 18 20:22:36 Pool-MCP kernel: intc0: Spurious interrupt detected
Apr 18 20:22:38 Pool-MCP kernel: local_intc0: Spurious interrupt detected
Apr 18 20:22:39 Pool-MCP kernel: intc0: Spurious interrupt detected
Apr 18 20:22:40 Pool-MCP syslogd: last message repeated 1 times
Apr 18 20:22:40 Pool-MCP kernel: local_intc0: Spurious interrupt detected
Apr 18 20:22:42 Pool-MCP kernel: intc0: Spurious interrupt detected
Apr 18 20:22:49 Pool-MCP kernel: local_intc0: Spurious interrupt detected
Apr 18 20:22:52 Pool-MCP kernel: intc0: Spurious interrupt detected
Apr 18 20:22:53 Pool-MCP kernel: local_intc0: Spurious interrupt detected

-- 
Karl Denninger
karl at denninger.net <mailto:karl at denninger.net>
/The Market Ticker/
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