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Re: [gpsd-dev] Linux kernel bug in 3:12, low_latency on serial ports is
From: |
Beat Bolli |
Subject: |
Re: [gpsd-dev] Linux kernel bug in 3:12, low_latency on serial ports is broken |
Date: |
Sat, 22 Feb 2014 23:25:58 +0100 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 |
It looks like help is on the way:
https://lkml.org/lkml/2014/2/22/44
Cheers,
Beat
On 20.02.14 12:14, Beat Bolli wrote:
> Hi Hal
>
> I had reported this to linux-serial:
> http://marc.info/?t=139125913700001&r=1&w=2
>
> I could not make sense of the replies, however.
>
> serial.c does not mention "low-latency" at all. Is the port->low_latency
> flag set by
> "session->ttyset.c_cc[VMIN] = 1;" in serial.c:494?
>
> Regards,
> Beat
>
> On 2014-02-20 09:31, Hal Murray wrote:
>> Just a heads-up in case you hit this, or want to avoid it.
>>
>> The symptom is BUG: scheduling while atomic
>> https://bugzilla.redhat.com/show_bug.cgi?id=1065087
>>
>> The discussion at
>> https://lkml.org/lkml/2014/2/18/77
>> confirms that it's the low-latency path that is buggy.
>>
>> My setup works fine under low load, but hits the BUG when I do
>> something like
>> compile the ntp package.
>>
>> 3.11 works fine. (for me) There was major work in the serial area
>> for 3.12
>>
>> I'll send an update when/if it gets fixed.
>
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