From fb0dc3993b537e12ce63511d535ff86efff13c8f Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Fri, 21 Apr 2017 16:19:23 -0700 Subject: [PATCH] nvme: Display raw APST configuration via DYNAMIC_DEBUG Debugging APST is currently a bit of a pain. This gives optional simple log messages that describe the APST state. The easiest way to use this is probably with the nvme_core.dyndbg=+p module parameter. Signed-off-by: Andy Lutomirski Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/nvme/host/core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 30446e29dbd9..3c9547b94541 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -1336,6 +1336,8 @@ static void nvme_configure_apst(struct nvme_ctrl *ctrl) unsigned apste; struct nvme_feat_auto_pst *table; + u64 max_lat_us = 0; + int max_ps = -1; int ret; /* @@ -1357,6 +1359,7 @@ static void nvme_configure_apst(struct nvme_ctrl *ctrl) if (ctrl->ps_max_latency_us == 0) { /* Turn off APST. */ apste = 0; + dev_dbg(ctrl->device, "APST disabled\n"); } else { __le64 target = cpu_to_le64(0); int state; @@ -1406,9 +1409,22 @@ static void nvme_configure_apst(struct nvme_ctrl *ctrl) target = cpu_to_le64((state << 3) | (transition_ms << 8)); + + if (max_ps == -1) + max_ps = state; + + if (total_latency_us > max_lat_us) + max_lat_us = total_latency_us; } apste = 1; + + if (max_ps == -1) { + dev_dbg(ctrl->device, "APST enabled but no non-operational states are available\n"); + } else { + dev_dbg(ctrl->device, "APST enabled: max PS = %d, max round-trip latency = %lluus, table = %*phN\n", + max_ps, max_lat_us, (int)sizeof(*table), table); + } } ret = nvme_set_features(ctrl, NVME_FEAT_AUTO_PST, apste, -- 2.20.1