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| author | Finn Thain <fthain@telegraphics.com.au> | 2016-01-03 06:05:19 +0100 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2016-01-07 03:42:55 +0100 |
| commit | 4d029e9ae9c382b149b16632f49970d8b215e2da (patch) | |
| tree | ecd48ef21f2f10c7020adebb701952d37b29c4bc /drivers/scsi/g_NCR5380.c | |
| parent | ncr5380: Keep BSY asserted when entering SELECTION phase (diff) | |
| download | linux-4d029e9ae9c382b149b16632f49970d8b215e2da.tar.xz linux-4d029e9ae9c382b149b16632f49970d8b215e2da.zip | |
ncr5380: Eliminate USLEEP_WAITLONG delay
Linux 2.1.105 introduced the USLEEP_WAITLONG delay, apparently "needed for
Mustek scanners". It is intended to stall the issue queue for 5 seconds.
There are a number of problems with this.
1. Only g_NCR5380 enables the delay, which implies that the other five
drivers using the NCR5380.c core driver remain incompatible with
Mustek scanners.
2. The delay is not implemented by atari_NCR5380.c, which is problematic
for re-unifying the two core driver forks.
3. The delay is implemented using NCR5380_set_timer() which makes it
unreliable. A new command queued by the mid-layer cancels the delay.
4. The delay is applied indiscriminately in several situations in which
NCR5380_select() returns -1. These are-- reselection by the target,
failure of the target to assert BSY, and failure of the target to
assert REQ. It's clear from the comments that USLEEP_WAITLONG is not
relevant to the reselection case. And reportedly, these scanners do
not disconnect.
5. atari_NCR5380.c was forked before Linux 2.1.105, so it was spared some
of the damage done to NCR5380.c. In this case, the atari_NCR5380.c core
driver was more standard-compliant and may not have needed any
workaround like the USLEEP_WAITLONG kludge. The compliance issue was
addressed in the previous patch.
If these scanners still don't work, we need a better solution. Retrying
selection until EH aborts a command offers equivalent robustness. Bugs in
the existing driver prevent EH working correctly but this is addressed in
a subsequent patch. Remove USLEEP_WAITLONG.
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to '')
| -rw-r--r-- | drivers/scsi/g_NCR5380.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c index ffbb07b0e9e8..fa9f6d41548b 100644 --- a/drivers/scsi/g_NCR5380.c +++ b/drivers/scsi/g_NCR5380.c @@ -59,7 +59,6 @@ /* settings for DTC3181E card with only Mustek scanner attached */ #define USLEEP_POLL msecs_to_jiffies(10) #define USLEEP_SLEEP msecs_to_jiffies(200) -#define USLEEP_WAITLONG msecs_to_jiffies(5000) #define AUTOPROBE_IRQ |