From: Andrew Morton <akpm@osdl.org>
To: Seokmann.Ju@lsil.com, Seokmann.Ju@engenio.com,
James.Bottomley@SteelEye.com, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH 1/1] megaraid_{mm,mbox}: fix a bug in reset handler
Date: Wed, 12 Apr 2006 22:05:34 -0700 [thread overview]
Message-ID: <20060412220534.379702c2.akpm@osdl.org> (raw)
In-Reply-To: <20060412220011.2ddd6f63.akpm@osdl.org>
Andrew Morton <akpm@osdl.org> wrote:
>
> > @@ -2918,12 +2933,12 @@
> > wmb();
> > WRINDOOR(raid_dev, raid_dev->mbox_dma | 0x1);
> >
> > - for (i = 0; i < 0xFFFFF; i++) {
> > + for (i = 0; i < 0xFFFFFF; i++) {
> > if (mbox->numstatus != 0xFF) break;
> > rmb();
> > }
>
> Oh my. That's an awfully long interrupts-off spin.
And if that mbox is in main memory, the duration of this spin will vary by
a factor of many tens across all the different machines on which this
driver must operate.
Careful use of ndelay() or udelay() would fix that.
next prev parent reply other threads:[~2006-04-13 5:05 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-12 13:09 Ju, Seokmann
2006-04-13 5:00 ` Andrew Morton
2006-04-13 5:05 ` Andrew Morton [this message]
2006-04-15 7:10 ` Andre Hedrick
2006-04-15 14:00 ` James Bottomley
2006-04-17 13:12 Ju, Seokmann
2006-04-18 14:50 Ju, Seokmann
2006-04-18 16:33 ` Andre Hedrick
2006-04-18 20:37 ` Andrew Morton
2006-04-18 17:28 Ju, Seokmann
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