Commit 4822827a authored by Finn Thain's avatar Finn Thain Committed by Martin K. Petersen
Browse files

scsi: ncr5380: Increase register polling limit 



If NCR5380_poll_politely() is called under irq lock, the polling time
limit is clamped to avoid a spike in interrupt latency. When not under
irq lock, the same polling time limit acts as the worst case delay
between schedule() calls.

During PDMA (under irq lock) I've found that the 10 ms time limit is
sometimes too short, and leads to the error message,
sd 0:0:0:0: [sda] tag#1 macscsi_pread: !REQ and !ACK

This particular target identifies itself as a QUANTUM DAYTONA514S. It
seems to be slower to assert ACK than the other targets I've tested.
This patch solves the problem by increasing the polling timeout.

Signed-off-by: default avatarFinn Thain <fthain@telegraphics.com.au>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Tested-by: default avatarOndrej Zary <linux@rainbow-software.org>
Tested-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent d4408dd7

drivers/scsi/NCR5380.h

+1 −1
Original line number Diff line number Diff line
@@ -253,7 +253,7 @@ 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		10

#define NCR5380_REG_POLL_TIME		15



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

{