From 14dc992aa782f8759c6d117d4322db62f62600ce Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Sun, 20 Jan 2008 01:25:31 +0100 Subject: [PATCH] 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 Acked-by: Jarod Wilson --- drivers/firewire/fw-sbp2.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c index 661a5b6..d2fbfc6 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)); -- 2.7.4