The patch titled sbp2: default to serialize_io=1 has been added to the -mm tree. Its filename is sbp2-default-to-serialize_io=1.patch From: Jody McIntyre sbp2: Set serialize_io=1 by default. This is safer and required by seemingly more and more hardware. It causes little or no performance loss for S400 devices. Performance of S800 1394b devices may drop by 25...30%. Therefore make the parameter's description and dmesg message clearer about performance impact. Update description of the max_speed parameter too. IEEE1394_SPEED_MAX is currently S800. Signed-off-by: Stefan Richter Signed-off-by: Jody McIntyre Cc: Ben Collins Signed-off-by: Andrew Morton --- drivers/ieee1394/sbp2.c | 11 +++++++---- 1 files changed, 7 insertions(+), 4 deletions(-) diff -puN drivers/ieee1394/sbp2.c~sbp2-default-to-serialize_io=1 drivers/ieee1394/sbp2.c --- 25/drivers/ieee1394/sbp2.c~sbp2-default-to-serialize_io=1 Thu Sep 22 15:07:10 2005 +++ 25-akpm/drivers/ieee1394/sbp2.c Thu Sep 22 15:07:10 2005 @@ -97,16 +97,18 @@ static char version[] __devinitdata = */ static int max_speed = IEEE1394_SPEED_MAX; module_param(max_speed, int, 0644); -MODULE_PARM_DESC(max_speed, "Force max speed (3 = 800mb, 2 = 400mb default, 1 = 200mb, 0 = 100mb)"); +MODULE_PARM_DESC(max_speed, "Force max speed (3 = 800mb, 2 = 400mb, 1 = 200mb, 0 = 100mb)"); /* * Set serialize_io to 1 if you'd like only one scsi command sent * down to us at a time (debugging). This might be necessary for very * badly behaved sbp2 devices. + * + * TODO: Make this configurable per device. */ -static int serialize_io; +static int serialize_io = 1; module_param(serialize_io, int, 0444); -MODULE_PARM_DESC(serialize_io, "Serialize all I/O coming down from the scsi drivers (default = 0)"); +MODULE_PARM_DESC(serialize_io, "Serialize I/O coming from scsi drivers (default = 1, faster = 0)"); /* * Bump up max_sectors if you'd like to support very large sized @@ -2857,7 +2859,8 @@ static int sbp2_module_init(void) /* Module load debug option to force one command at a time (serializing I/O) */ if (serialize_io) { - SBP2_ERR("Driver forced to serialize I/O (serialize_io = 1)"); + SBP2_INFO("Driver forced to serialize I/O (serialize_io=1)"); + SBP2_INFO("Try serialize_io=0 for better performance"); scsi_driver_template.can_queue = 1; scsi_driver_template.cmd_per_lun = 1; } _ Patches currently in -mm which might be from scjody@steamballoon.com are maintainers-sbp2-driver-is-not-orphaned.patch sbp2-fix-deadlocks-and-delays-on-device-removal-rmmod.patch sbp2-default-to-serialize_io=1.patch ieee1394-reorder-activities-after-bus-reset-fixes-device-detection.patch ieee1394-skip-unnecessary-pause-when-scanning-config-roms.patch ieee1394-fix-for-debug-output.patch ieee1394-use-time_before.patch ieee1394-trivial-edits-of-a-few-comments.patch ieee1394-remove-superfluous-include-in-csr1212.patch eth1394-workaround-limitation-in-rawiso-routines.patch ieee1394-delete-legacy-module-aliases.patch ohci1394-less-noise-in-dmesg.patch