From: Leon Woestenberg <leon.woestenberg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
rt-users <linux-rt-users-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"Jean Delvare (PC drivers,
core)" <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>,
"Ben Dooks (embedded platforms)"
<ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
Subject: yield() in i2c non-happy paths hits BUG under -rt patch
Date: Sat, 7 Nov 2009 20:01:59 +0100 [thread overview]
Message-ID: <c384c5ea0911071101u7415d37o2611c542e5fae309@mail.gmail.com> (raw)
Hello Jean, Ben, -i2c and -rt devs,
during testing the Linux PREEMP_RT work (step-by-step being merged
with mainline) together with I2C functionality I hit the fact that the
I2C
subsystem uses yield() in some of the non-happy code paths (mostly
during chip / address probing etc).
My (embedded) system was running a low-priority real-time work on the
generic workqueue which tried to blink a LED using an I2C I/O
multiplexer
when I hit the BUG where this real-time task ran into the yield() of
try_address().
Grepping through the I2C subsystem code there where more yield()
sprinkled in, without it being clear to me why they are there.
Can those yield()s please be removed, and if they are needed for some
reason (??) be replaced with something equivalent?
I am no longer with this particular project, I do not have the
defconfig and kernel logs at my disposal.
Regards,
--
Leon
next reply other threads:[~2009-11-07 19:01 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-07 19:01 Leon Woestenberg [this message]
[not found] ` <c384c5ea0911071101u7415d37o2611c542e5fae309-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-11-07 20:01 ` yield() in i2c non-happy paths hits BUG under -rt patch Jean Delvare
[not found] ` <20091107210147.3e754278-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org>
2009-11-08 18:57 ` Sven-Thorsten Dietrich
[not found] ` <4AF7148C.9090706-IsH+rWyeNGyzjR9+/8zPv5owlv4uC7bZ@public.gmane.org>
2009-11-12 20:12 ` Jean Delvare
2009-11-13 22:03 ` Thomas Gleixner
2009-11-14 18:02 ` Jean Delvare
[not found] ` <alpine.LFD.2.00.0911132139560.24119-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2009-11-16 15:56 ` Mark Brown
[not found] ` <20091116155606.GC29479-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2009-11-18 0:50 ` Leon Woestenberg
2009-11-18 1:05 ` Alan Cox
[not found] ` <20091118010520.4cd397d4-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
2009-11-18 16:28 ` Leon Woestenberg
2009-11-18 16:52 ` Jean Delvare
[not found] ` <20091118175202.490989d8-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org>
2009-11-18 20:36 ` Thomas Gleixner
2009-11-19 12:05 ` Jean Delvare
[not found] ` <20091119130526.23a69b85-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org>
2009-11-19 12:59 ` Alan Cox
[not found] ` <20091119125906.6ad00edd-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
2009-11-19 13:06 ` Peter Zijlstra
2009-11-19 14:00 ` Jean Delvare
2009-11-19 14:15 ` Peter Zijlstra
2009-11-19 13:11 ` Thomas Gleixner
2009-11-19 13:21 ` Peter Zijlstra
2009-11-19 13:22 ` Thomas Gleixner
2009-11-19 13:18 ` Peter Zijlstra
2009-11-18 20:46 ` [PATCH] cleanup sched_yield (sys)call nesting Sven-Thorsten Dietrich
[not found] ` <1258577194.12429.86.camel-ZUMNgey8dAdBci4yedNfAfz91O0DMRRp0E9HWUfgJXw@public.gmane.org>
2009-11-18 20:56 ` Thomas Gleixner
[not found] ` <alpine.LFD.2.00.0911182153010.24119-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2009-11-18 21:04 ` Sven-Thorsten Dietrich
2009-11-18 21:34 ` Thomas Gleixner
[not found] ` <alpine.LFD.2.00.0911182233510.24119-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2009-11-19 4:48 ` Sven-Thorsten Dietrich
[not found] ` <1258606116.25022.57.camel-ZUMNgey8dAdBci4yedNfAfz91O0DMRRp0E9HWUfgJXw@public.gmane.org>
2009-11-19 10:36 ` Thomas Gleixner
2009-11-19 3:20 ` Ingo Molnar
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