android_kernel_xiaomi_sdm845/drivers/scsi/sym53c8xx_2
Tony Battersby c2fd206e08 [SCSI] sym53c8xx: use a queue depth of 1 for untagged devices
sym53c8xx uses a command queue depth of 2 for untagged devices,
without good reason.  This _mostly_ seems to work ok, but it has
caused me some subtle problems.  For example, I have an application
where one thread sends write commands to a tape drive, and another
thread sends log sense polling commands.  With a queue depth of
2, the polling commands end up being starved for long periods of
time while multiple write commands are serviced (this may also be
related to the fact the the sg driver queues commands in LIFO order).
This problem is fixed by changing the queue depth to 1 for untagged
devices.  I have tested this change extensively with many different
tape drives, medium changers, and disk drives (disk drives of course
use tagged commands and are therefore unaffected by this patch).

Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-03-12 12:58:17 -05:00
..
Makefile Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sym53c8xx.h [SCSI] sym53c8xx: Remove tag_ctrl module parameter 2007-10-23 15:11:57 -04:00
sym_defs.h [SCSI] Version 2.2.3 2006-04-13 10:13:26 -05:00
sym_fw1.h Fix misspellings of "agressive". 2007-02-17 19:20:16 +01:00
sym_fw2.h Spelling fix: explicitly 2007-10-19 23:22:55 +02:00
sym_fw.c [SCSI] sym53c8xx: Remove pci_dev pointer from sym_shcb 2007-10-23 15:26:34 -04:00
sym_fw.h [SCSI] sym53c8xx: Remove pci_dev pointer from sym_shcb 2007-10-23 15:26:34 -04:00
sym_glue.c [SCSI] sym53c8xx: use a queue depth of 1 for untagged devices 2009-03-12 12:58:17 -05:00
sym_glue.h [SCSI] sym53c8xx: Remove sym_xpt_async_sent_bdr 2007-10-23 15:26:56 -04:00
sym_hipd.c [SCSI] sym53c8xx: Keep transfer negotiations valid 2009-03-12 12:57:57 -05:00
sym_hipd.h [SCSI] sym53c8xx: Keep transfer negotiations valid 2009-03-12 12:57:57 -05:00
sym_malloc.c [SCSI] sym2: Remove FreeBSD ifdefs 2005-12-13 18:11:27 -07:00
sym_misc.h [SCSI] sym53c8xx: Fix bogus sym_que_entry re-implementation of container_of 2008-07-12 08:22:37 -05:00
sym_nvram.c [SCSI] sym53c8xx: Remove ->device_id 2007-10-23 15:11:10 -04:00
sym_nvram.h [SCSI] sym2: Allow NVRAM settings to limit speed and width 2005-12-13 18:11:45 -07:00