[SCSI] st: add option to use SILI in variable block reads
Add new option MT_ST_SILI to enable setting the SILI bit in reads in variable
block mode. If SILI is set, reading a block shorter than the byte count does
not result in CHECK CONDITION. The length of the block is determined using the
residual count from the HBA. Avoiding the REQUEST SENSE command for every
block speeds up some real applications considerably.
Signed-off-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt
index b7be95b..38f8118 100644
--- a/Documentation/scsi/st.txt
+++ b/Documentation/scsi/st.txt
@@ -2,7 +2,7 @@
The driver is currently maintained by Kai Mäkisara (email
Kai.Makisara@kolumbus.fi)
-Last modified: Mon Mar 7 21:14:44 2005 by kai.makisara
+Last modified: Thu Feb 21 21:54:16 2008 by kai.makisara
BASICS
@@ -372,6 +372,11 @@
MT_ST_SYSV sets the SYSV semantics (mode)
MT_ST_NOWAIT enables immediate mode (i.e., don't wait for
the command to finish) for some commands (e.g., rewind)
+ MT_ST_SILI enables setting the SILI bit in SCSI commands when
+ reading in variable block mode to enhance performance when
+ reading blocks shorter than the byte count; set this only
+ if you are sure that the drive supports SILI and the HBA
+ correctly returns transfer residuals
MT_ST_DEBUGGING debugging (global; debugging must be
compiled into the driver)
MT_ST_SETBOOLEANS