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authorStefan Richter <stefanr@s5r6.in-berlin.de>2008-01-20 01:25:31 +0100
committerStefan Richter <stefanr@s5r6.in-berlin.de>2008-01-30 22:22:26 +0100
commit14dc992aa782f8759c6d117d4322db62f62600ce (patch)
tree5f29e0420fd3a310ee86c4222bfa79c70f4d06ae /drivers/firewire
parent4dccd020d7ca5e673d7804cc4ff80fbf58d8a37e (diff)
firewire: fw-sbp2: try to increase reconnect_hold (speed up reconnection)
Ask the target to grant 4 seconds instead of the standard and minimum of 1 second window after bus reset for reconnection. This accelerates reconnection if there are more than one targets on the bus: If a login and inquiry to one target blocks the fw-sbp2 workqueue for more than 1s after bus reset, we now still can reconnect to the other target. Before that, fw-sbp2's reconnect attempts would be rejected with "error status: 0:9" (function rejected), and fw-sbp2 would finally re-login. All those futile reconnect attemps cost extra time until the target which needs re-login is ready for I/O again. The reconnect timeout field in the login ORB doesn't have to be honored by the target though. I found that we could get up to - allegedly 32768s from an old OXFW911 firmware - 256s from LSI bridges - 4s from OXUF922 and OXFW912 bridges, - 2s from TI bridges, - only the standard 1s from Initio and Prolific bridges and from Apple OpenFirmware in target mode. We just try to get 4 seconds which already covers the case of a few HDDs on the same bus quite nicely. A minor drawback occurs in the following (rare and impractical) border case: - two initiators are there, initiator 1 holds an exclusive login to a target, - initiator 1 goes off the bus, - target refuses login attempts from initiator 2 until reconnect_hold seconds after bus reset. An alternative approach to the issue at hand would be to parallelize fw-sbp2's reconnect and login work. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Acked-by: Jarod Wilson <jwilson@redhat.com>
Diffstat (limited to 'drivers/firewire')
-rw-r--r--drivers/firewire/fw-sbp2.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c
index 661a5b66f661..d2fbfc6f6d8a 100644
--- a/drivers/firewire/fw-sbp2.c
+++ b/drivers/firewire/fw-sbp2.c
@@ -514,9 +514,10 @@ sbp2_send_management_orb(struct sbp2_logical_unit *lu, int node_id,
orb->request.status_fifo.low = lu->address_handler.offset;
if (function == SBP2_LOGIN_REQUEST) {
+ /* Ask for 2^2 == 4 seconds reconnect grace period */
orb->request.misc |=
- MANAGEMENT_ORB_EXCLUSIVE(sbp2_param_exclusive_login) |
- MANAGEMENT_ORB_RECONNECT(0);
+ MANAGEMENT_ORB_RECONNECT(2) |
+ MANAGEMENT_ORB_EXCLUSIVE(sbp2_param_exclusive_login);
}
fw_memcpy_to_be32(&orb->request, &orb->request, sizeof(orb->request));