ncr5380: Dont wait for BUS FREE after disconnect
authorFinn Thain <fthain@telegraphics.com.au>
Sun, 3 Jan 2016 05:05:36 +0000 (16:05 +1100)
committerMartin K. Petersen <martin.petersen@oracle.com>
Thu, 7 Jan 2016 02:42:59 +0000 (21:42 -0500)
commit401e79fe8d9f0151ad99e6fd7c1bd2e178c84d25
tree744e730f759c3efa38bd5312d5db6f492175cab2
parent55500d9b08295e3b6016b53879dea1cb7787f1b0
ncr5380: Dont wait for BUS FREE after disconnect

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@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
drivers/scsi/NCR5380.c
drivers/scsi/atari_NCR5380.c