From mboxrd@z Thu Jan  1 00:00:00 1970
From: James Bottomley <James.Bottomley@SteelEye.com>
Subject: RE: [Bugme-new] [Bug 8426] New: massive slowdown on SCSI
	CD/DVDdrive connected to mptspi driver
Date: Fri, 04 May 2007 17:58:52 -0500
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To: Doug Chapman <doug.chapman@hp.com>
Cc: "Moore, Eric" <Eric.Moore@lsi.com>, Andrew Morton <akpm@linux-foundation.org>, linux-scsi@vger.kernel.org, "bugme-daemon@kernel-bugs.osdl.org" <bugme-daemon@bugzilla.kernel.org>

On Fri, 2007-05-04 at 17:56 -0400, Doug Chapman wrote:
> I am applying/removing _only_ your patch and the problem goes away with
> just removing it.

What id and channel is this DVD drive on?  There is a potential bug in
the move:

-mptscsih_writeIOCPage4(MPT_SCSI_HOST *hd, int channel, int id)
+mptspi_writeIOCPage4(MPT_SCSI_HOST *hd, u8 channel , u8 id)

Note int became u8, but later we have:


	pReq->PageAddress = cpu_to_le32(id | (channel << 8 ));

channel << 8 is always zero as a u8 entity (unless something promotes
the arithmetic beyond u8).  So if the DVD is on a non-zero channel, we
might have our cause.

James