From: Jeremy Higdon Date: Mon, 12 May 2008 06:17:03 +0000 (-0700) Subject: [SCSI] qla1280: Fix queue depth problem X-Git-Tag: v2.6.26-rc3~69^2 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=af5741c6de4f4a1d8608b0f00867c77cb7123635;p=linux-2.6 [SCSI] qla1280: Fix queue depth problem The qla1280 driver was ANDing the output value of mailbox register 0 with (1 << target-number) to determine whether to enable queueing on the target in question. But mailbox register 0 has the status code for the mailbox command (in this case, Set Target Parameters). Potential values are: /* * ISP mailbox command complete status codes */ So clearly that is in error. I can't think what the author of that line was looking for in a mailbox register, so I just eliminated the AND. flag is used later in the function, and I think that the later usage was also wrong, though it was used to set values that aren't used. Oh well, an overhaul of this driver is not what I want to do now -- just a bugfix. After the fix, I found that my disks were getting a queue depth of 255, which is far too many. Most SCSI disks are limited to 32 or 64. In any case, there's no point, queueing up a bunch of commands to the adapter that will just result in queue full or starve other targets from being issued commands due to running out of internal memory. So I dropped default queue depth to 32 (from which 1 is subtracted elsewhere, giving net of 31). I tested with a Seagate ST336753LC, and results look good, so I'm satisfied with this patch. Signed-off-by: Jeremy Higdon Acked-by: Jes Sorensen Cc: Stable Tree Signed-off-by: James Bottomley --- diff --git a/drivers/scsi/qla1280.c b/drivers/scsi/qla1280.c index fa060932d2..51e2f299db 100644 --- a/drivers/scsi/qla1280.c +++ b/drivers/scsi/qla1280.c @@ -2007,7 +2007,7 @@ qla1280_set_defaults(struct scsi_qla_host *ha) nv->bus[bus].config_2.req_ack_active_negation = 1; nv->bus[bus].config_2.data_line_active_negation = 1; nv->bus[bus].selection_timeout = 250; - nv->bus[bus].max_queue_depth = 256; + nv->bus[bus].max_queue_depth = 32; if (IS_ISP1040(ha)) { nv->bus[bus].bus_reset_delay = 3; @@ -2051,7 +2051,7 @@ qla1280_config_target(struct scsi_qla_host *ha, int bus, int target) status = qla1280_mailbox_command(ha, 0x0f, mb); /* Save Tag queuing enable flag. */ - flag = (BIT_0 << target) & mb[0]; + flag = (BIT_0 << target); if (nv->bus[bus].target[target].parameter.tag_queuing) ha->bus_settings[bus].qtag_enables |= flag;