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authorStefan Richter <stefanr@s5r6.in-berlin.de>2007-12-16 11:31:26 -0500
committerStefan Richter <stefanr@s5r6.in-berlin.de>2008-01-30 16:22:21 -0500
commit4e6343a10b6afb5b036db35c4a0f0aa1333232e1 (patch)
tree3c519551bad718cc1006d570e43a2f51a6befd1d /drivers/ieee1394/sbp2.h
parent3e75b493fbfad5d70831a2f7267c7cd8b8fec71f (diff)
ieee1394: sbp2: raise default transfer size limit
This patch speeds up sbp2 a little bit --- but more importantly, it brings the behavior of sbp2 and fw-sbp2 closer to each other. Like fw-sbp2, sbp2 now does not limit the size of single transfers to 255 sectors anymore, unless told so by a blacklist flag or by module load parameters. Only very old bridge chips have been known to need the 255 sectors limit, and we have got one such chip in our hardwired blacklist. There certainly is a danger that more bridges need that limit; but I prefer to have this issue present in both fw-sbp2 and sbp2 rather than just one of them. An OXUF922 with 400GB 7200RPM disk on an S400 controller is sped up by this patch from 22.9 to 23.5 MB/s according to hdparm. The same effect could be achieved before by setting a higher max_sectors module parameter. On buses which use 1394b beta mode, sbp2 and fw-sbp2 will now achieve virtually the same bandwidth. Fw-sbp2 only remains faster on 1394a buses due to fw-core's gap count optimization. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Diffstat (limited to 'drivers/ieee1394/sbp2.h')
-rw-r--r--drivers/ieee1394/sbp2.h1
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/ieee1394/sbp2.h b/drivers/ieee1394/sbp2.h
index 333a4bb76743..d2ecb0d8a1bb 100644
--- a/drivers/ieee1394/sbp2.h
+++ b/drivers/ieee1394/sbp2.h
@@ -222,7 +222,6 @@ struct sbp2_status_block {
222 */ 222 */
223 223
224#define SBP2_MAX_SG_ELEMENT_LENGTH 0xf000 224#define SBP2_MAX_SG_ELEMENT_LENGTH 0xf000
225#define SBP2_MAX_SECTORS 255
226/* There is no real limitation of the queue depth (i.e. length of the linked 225/* There is no real limitation of the queue depth (i.e. length of the linked
227 * list of command ORBs) at the target. The chosen depth is merely an 226 * list of command ORBs) at the target. The chosen depth is merely an
228 * implementation detail of the sbp2 driver. */ 227 * implementation detail of the sbp2 driver. */