From 18e3ee2cf96adf072deeb291eed670f2c23bb2fc Mon Sep 17 00:00:00 2001 From: Steve Hodgson Date: Thu, 2 Dec 2010 13:46:55 +0000 Subject: [PATCH] sfc: Fix event based MCDI completion and MC REBOOT/CMDDONE ordering issue The mcfw *never* sends CMDDONE when rebooting. Changing this so that it always sends CMDDONE *before* REBOOT is easy on Siena, but it's not obvious that we could guarantee to be able to implement this on future hardware. Given this, I'm less convinced that the protocol should be changed. To reiterate the failure mode: The driver sees this: issue command receive REBOOT event Was that reboot event sent before the command was issued, or in response to the command? If the former then there will be a subsequent CMDDONE event, if the latter, then there will be no CMDDONE event. Options to resolve this are: 1. REBOOT always completes an outstanding mcdi request, and we set the credits count to ignore a subsequent CMDDONE event with mismatching seqno. 2. REBOOT never completes an outstanding mcdi request. If there is no CMDDONE event then we rely on the mcdi timeout code to complete the outstanding request, incurring a 10s delay. I'd argue that (2) is tidier, but that incurring a 10s delay is a little needless. Let's go with (1). Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/sfc/mcdi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/sfc/mcdi.c b/drivers/net/sfc/mcdi.c index e389ac6c214f..b716e827b291 100644 --- a/drivers/net/sfc/mcdi.c +++ b/drivers/net/sfc/mcdi.c @@ -463,6 +463,7 @@ static void efx_mcdi_ev_death(struct efx_nic *efx, int rc) if (mcdi->mode == MCDI_MODE_EVENTS) { mcdi->resprc = rc; mcdi->resplen = 0; + ++mcdi->credits; } } else /* Nobody was waiting for an MCDI request, so trigger a reset */ -- 2.20.1