From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: avorontsov@ru.mvista.com
Cc: Ingo Molnar <mingo@elte.hu>,
linux-ide@vger.kernel.org,
Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Daniel Walker <dwalker@mvista.com>
Subject: Re: [PATCH v2 -rt] ide: workaround buggy hardware issues with preemptable hardirqs
Date: Sat, 28 Jun 2008 15:52:02 +0400 [thread overview]
Message-ID: <486625E2.2020808@ru.mvista.com> (raw)
In-Reply-To: <20080628113126.GA438@polina.dev.rtsoft.ru>
Hello.
Anton Vorontsov wrote:
>>> But some hardware (namely ULi M5228 in the ULi M1575 "Super South Brige")
>>> behaves in a strange way: it asserts interrupts as edge sensitive. And
>>> because preemptable IRQ handler disables PIC's interrupt, PIC will likely
>>> miss it.
>>>
>>>
>> Unmasking an IRQ should re-enable an edge detector in a PIC (or that
>> detector should even be independent from mask).
>>
> Should? Hm.. well, I can easily check it. Will just program the MPIC IRQ
> to edge sensitive, and see if it fixes the problem (not sure if I already
> tried this, I think I did try).
>
That will not help if edge detector is not active for masked out IRQs
(that's how i8259 behaves, IIRC) *and* you're getting the short IRQ
"pulses" but should help if IRQ is generated normally -- though in this
case the level trigger mode (with the same polarity) should work as well...
MBR, Sergei
next prev parent reply other threads:[~2008-06-28 11:52 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-23 23:40 [PATCH -rt] ide: fix interrupts processing issue with preempt-able hardirqs Anton Vorontsov
2008-06-23 23:51 ` Ingo Molnar
2008-06-24 0:00 ` Anton Vorontsov
2008-06-25 12:34 ` Anton Vorontsov
2008-06-25 12:32 ` Alan Cox
2008-06-25 14:12 ` Anton Vorontsov
2008-06-25 13:15 ` Sergei Shtylyov
2008-06-25 14:22 ` Anton Vorontsov
2008-06-25 14:32 ` Alan Cox
2008-06-25 15:26 ` Anton Vorontsov
2008-06-25 14:59 ` Anton Vorontsov
2008-06-28 0:54 ` [PATCH v2 -rt] ide: workaround buggy hardware issues with preemptable hardirqs Anton Vorontsov
2008-06-28 1:09 ` Anton Vorontsov
2008-06-28 9:15 ` Alan Cox
2008-06-28 9:14 ` Alan Cox
2008-06-28 10:43 ` Sergei Shtylyov
2008-06-29 12:49 ` Alan Cox
2008-06-29 13:17 ` Sergei Shtylyov
2008-06-29 14:23 ` Anton Vorontsov
2008-06-28 10:30 ` Sergei Shtylyov
2008-06-28 11:31 ` Anton Vorontsov
2008-06-28 11:52 ` Sergei Shtylyov [this message]
2008-06-29 23:26 ` Benjamin Herrenschmidt
2008-06-30 19:01 ` [RT] MPIC edge sensitive issues with hardirq preemption (was: Re: [PATCH v2 -rt] ide: workaround buggy hardware issues with preemptable hardirqs) Anton Vorontsov
2008-06-30 21:59 ` Benjamin Herrenschmidt
2008-06-30 22:37 ` Anton Vorontsov
2008-07-01 10:41 ` [RT] MPIC edge sensitive issues with hardirq preemption Sergei Shtylyov
2008-07-01 11:34 ` Anton Vorontsov
2008-06-23 23:52 ` [PATCH -rt] ide: fix interrupts processing issue with preempt-able hardirqs Anton Vorontsov
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