[8081] in linux-scsi channel archive
Re: Kernel v2.2.15pre5 SCSI 2940U2W with AIC7895 boot still
daemon@ATHENA.MIT.EDU (M Sweger)
Thu Feb 10 16:01:23 2000
Date: Thu, 10 Feb 2000 14:19:02 -0500 (EST)
From: M Sweger <mikesw@whiterose.net>
To: Doug Ledford <dledford@redhat.com>
Cc: Benjamin Herrenschmidt <bh40@calva.net>, alan@redhat.com,
linux-scsi@vger.rutgers.edu, linux-kernel@vger.rutgers.edu
In-Reply-To: <38A2A93A.808EDF84@redhat.com>
Message-ID: <Pine.LNX.4.21.0002101416530.10676-100000@whiterose.net>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
On Thu, 10 Feb 2000, Doug Ledford wrote:
> M Sweger wrote:
>
> > > > scsi : 3 hosts.
> > > > (scsi0:0:0:0) Synchronous at 40.0 Mbyte/sec, offset 8.
> > > > (scsi0:0:0:0) Data overrun detected in Data-In phase, tag 1;
> > > > Have seen Data Phase. Length=255, NumSGs=1.
> > > > sg[0] - Addr 0x7fec380 : Length 255
> > > > Vendor: WDIGTL Model: WDE9100-1807A4 Rev: 1.30
> > > > Type: Direct-Access ANSI SCSI revision: 02
> > > > Detected scsi disk sda at scsi0, channel 0, id 0, lun 0
>
> [ snip ]
>
> > Although 2.2.13 gives the same data overrun message, 2.2.1 didn't.
>
> > scsi : 3 hosts.
> > Vendor: WDIGTL Model: WDE9100-1807A4 Rev: 1.30
> > Type: Direct-Access ANSI SCSI revision: 02
> > Detected scsi disk sda at scsi0, channel 0, id 0, lun 0
> > (scsi0:0:0:0) Synchronous at 40.0 Mbyte/sec, offset 8.
>
> This is to be expected. You aren't getting the error in the old drive not
> because the sequencer doesn't have the bug, but because the INQUIRY is
> happening before we negotiate WIDE transfer mode. The actual overrun is
> because we have an odd INQUIRY buffer length and WIDE transfer which means we
> get an extra byte from the drive and the current version of the driver is
> seeing that extra byte as an overrun instead of a wide residue. This only
> happens on your drive type because most drives don't bother to send in enough
> data to fill in the entire 255 byte buffer.
>
Ok! So should I just incrase the array buffer size to a power of 2: that
is 256! and then I won't get any buffer overruns?
Then the aic7xxx driver can handle my drive and those other drives.
MIke
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