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Message-ID: <5678FC3F.5040507@suse.de>
Date: Tue, 22 Dec 2015 08:31:11 +0100
From: Hannes Reinecke <hare@...e.de>
To: Finn Thain <fthain@...egraphics.com.au>,
"James E.J. Bottomley" <JBottomley@...n.com>,
Michael Schmitz <schmitzmic@...il.com>,
linux-m68k@...r.kernel.org, linux-scsi@...r.kernel.org,
linux-kernel@...r.kernel.org,
"Martin K. Petersen" <martin.petersen@...cle.com>
Subject: Re: [PATCH v3 35/77] ncr5380: Dont wait for BUS FREE after disconnect
On 12/22/2015 02:18 AM, Finn Thain wrote:
> When there is a queued command and no connected command, NCR5380_select()
> is called and arbitration begins. The chip waits for BUS FREE once the
> MR_ARBITRATE bit in the mode register is enabled. That means there is
> no need to wait for BUS FREE after disconnecting.
>
> There is presently no polling for BUS FREE after sending an ABORT or
> other message that might lead to disconnection. It only happens after
> COMMAND COMPLETE or DISCONNECT messages, which seems inconsistent.
> Remove the polling for !BSY in the COMMAND COMPLETE and DISCONNECT
> cases.
>
> BTW, the comments say "avoid nasty timeouts" and perhaps BUS FREE polling
> was somehow helpful back in Linux v0.99.14u, when it was introduced.
> The relevant timeout is presently 1 second (for bus arbitration).
>
> Signed-off-by: Finn Thain <fthain@...egraphics.com.au>
>
> ---
> drivers/scsi/NCR5380.c | 7 -------
> drivers/scsi/atari_NCR5380.c | 11 -----------
> 2 files changed, 18 deletions(-)
>
Reviewed-by: Hannes Reinecke <hare@...e.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@...e.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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