From: anti.sullin@artecdesign•ee (Anti Sullin)
To: linux-arm-kernel@lists•infradead.org
Subject: [patch v2 1/2] at91_udc.c read_fifo timing issue
Date: Mon, 01 Feb 2010 00:34:44 +0200 [thread overview]
Message-ID: <4B660584.7020302@artecdesign.ee> (raw)
In-Reply-To: <20100129162155.709756286@gmail.com>>
Harro Haan wrote:
> This solves the read_fifo timing issue for example seen with CDC
Ethernet.
[...]
Still this bug not fixed?
I sent almost the same fix and a lot of debug info with description of
the issue and the critical path of the timing to linux-arm-kernel on
2009-03-25 (
http://lists.arm.linux.org.uk/lurker/message/20090325.150843.f515c02f.en.html
) and we had an off-list discussion with David Brownell about another
udc patch on 2009-06-19 that later turned out to be the same issue.
This fix has solved the problems on our devices and we've been using it
for almost a year now.
About Harro's patch:
* why are the marker1 and marker2 comments necessary to be included?
* maybe you should just link to the mailing list and/or move the long
comment to patch description instead adding a page-long comment to code;
just leave a small comment to explain why the work-around is needed so
that nobody would optimize it away?
* Is the error check and warning message necessary after we've got rid
of the problem? Won't it add problems - as I found out, the first csr
read (that comes too early) may return bogus data, you should not use
its result at all.
--
Anti Sullin
Embedded Software Engineer
Artec Design LLC
Teaduspargi 6/2, 12618, Tallinn, Estonia
http://www.artecdesign.ee
next prev parent reply other threads:[~2010-01-31 22:34 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-27 16:30 [patch 0/2] at91_udc driver: read_fifo timing issue + use spinlocks Harro Haan
2010-01-27 16:30 ` [patch 1/2] at91_udc.c read_fifo timing issue Harro Haan
2010-01-27 16:30 ` [patch 2/2] at91_udc.c use spinlocks instead of local_irq_xxx Harro Haan
2010-01-27 17:37 ` H Hartley Sweeten
2010-01-28 12:52 ` Harro Haan
2010-01-29 16:20 ` [patch v2 0/2] at91_udc driver: read_fifo timing issue + use spinlocks Harro Haan
2010-01-29 16:20 ` [patch v2 1/2] at91_udc.c read_fifo timing issue Harro Haan
2010-01-29 17:04 ` Remy Bohmer
2010-01-31 20:08 ` Ryan Mallon
2010-01-31 22:34 ` Anti Sullin [this message]
2010-02-03 14:37 ` [patch v3 0/3] at91_udc: fix soft lockup, HW glitch and use spinlocks Harro Haan
2010-02-03 14:37 ` [patch v3 1/3] Fix soft lockup in at91 udc driver Harro Haan
2010-02-03 14:37 ` [patch v3 2/3] at91_udc HW glitch Harro Haan
2010-03-23 20:26 ` Andrew Victor
2010-03-25 12:03 ` Harro Haan
2010-03-25 13:09 ` Anti Sullin
2010-02-03 14:37 ` [patch v3 3/3] at91_udc.c use spinlocks instead of local_irq_xxx Harro Haan
2010-01-29 16:20 ` [patch v2 2/2] " Harro Haan
2010-01-29 17:27 ` H Hartley Sweeten
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