From: James Bottomley <James.Bottomley@suse.de>
To: Ben Hutchings <ben@decadent.org.uk>
Cc: linux-scsi@vger.kernel.org
Subject: Re: [PATCH] atp870u: Split long udelay()
Date: Fri, 19 Feb 2010 09:28:19 -0600 [thread overview]
Message-ID: <1266593299.2822.7.camel@mulgrave.site> (raw)
In-Reply-To: <1266544619.10567.715.camel@localhost>
On Fri, 2010-02-19 at 01:56 +0000, Ben Hutchings wrote:
> udelay() is supposed to be limited to 1 ms, and will generate a
> __bad_udelay() on ARM for constant arguments > 2000. Split
> udelay(0x800) into mdelay(2); udelay(48). (I suspect that msleep(3)
> would work but I do not know how critical the timing is here.)
So no to this one. Either ARM is right and udelay > 2000 is wrong
(which actually sounds correct given how long this will eat CPU for) so
the driver needs fixing, or ARM is wrong and the warning needs fixing.
Splitting the delay to defeat the warning while retaining the behaviour
it was trying to warn about is the wrong thing to do.
James
next prev parent reply other threads:[~2010-02-19 15:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-19 1:56 [PATCH] atp870u: Split long udelay() Ben Hutchings
2010-02-19 15:28 ` James Bottomley [this message]
2010-02-19 16:44 ` Ben Hutchings
2010-02-27 21:17 ` Ben Hutchings
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