Revert "scsi: ncr5380: Increase register polling limit" [Linux 5.3]

This Linux kernel change "Revert “scsi: ncr5380: Increase register polling limit”" is included in the Linux 5.3 release. This change is authored by Finn Thain <fthain [at] telegraphics.com.au> on Sun Jun 9 11:19:11 2019 +1000. The commit for this change in Linux stable tree is 25fcf94 (patch).

Revert "scsi: ncr5380: Increase register polling limit"

This reverts commit 4822827a69d7cd3bc5a07b7637484ebd2cf88db6.

The purpose of that commit was to suppress a timeout warning message which
appeared to be caused by target latency. But suppressing the warning is
undesirable as the warning may indicate a messed up transfer count.

Another problem with that commit is that 15 ms is too long to keep
interrupts disabled as interrupt latency can cause system clock drift and
other problems.

Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: stable@vger.kernel.org
Fixes: 4822827a69d7 ("scsi: ncr5380: Increase register polling limit")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/scsi/NCR5380.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/NCR5380.h b/drivers/scsi/NCR5380.h
index efca509b9..5935fd6 100644
--- a/drivers/scsi/NCR5380.h
+++ b/drivers/scsi/NCR5380.h
@@ -235,7 +235,7 @@ struct NCR5380_cmd {
 #define NCR5380_PIO_CHUNK_SIZE     256

 /* Time limit (ms) to poll registers when IRQs are disabled, e.g. during PDMA */
-#define NCR5380_REG_POLL_TIME      15
+#define NCR5380_REG_POLL_TIME      10

 static inline struct scsi_cmnd *NCR5380_to_scmd(struct NCR5380_cmd *ncmd_ptr)
 {

Leave a Reply

Your email address will not be published. Required fields are marked *