Re: Kernel v2.2.15pre5 SCSI 2940U2W with AIC7895 boot still broke(withfix).

From: M Sweger (mikesw@whiterose.net)
Date: Thu Feb 10 2000 - 14:19:02 EST


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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