[PATCH v2 2/2] nvme: hwmon: add quirk to avoid changing temperature threshold

[Akinobu Mita <akinobu.mita@gmail.com>]

This adds a new quirk NVME_QUIRK_NO_TEMP_THRESH_CHANGE to avoid changing
the value of the temperature threshold feature for specific devices that
show undesirable behavior.

Guenter reported:

"On my Intel NVME drive (SSDPEKKW512G7), writing any minimum limit on the
Composite temperature sensor results in a temperature warning, and that
warning is sticky until I reset the controller.

It doesn't seem to matter which temperature I write; writing -273000 has
the same result."

The Intel NVMe has the latest firmware version installed, so this isn't
a problem that was ever fixed.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 drivers/nvme/host/nvme-hwmon.c | 6 +++++-
 drivers/nvme/host/nvme.h       | 5 +++++
 drivers/nvme/host/pci.c        | 3 ++-
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/nvme-hwmon.c b/drivers/nvme/host/nvme-hwmon.c
index 97a84b4..a5af21f 100644
--- a/drivers/nvme/host/nvme-hwmon.c
+++ b/drivers/nvme/host/nvme-hwmon.c
@@ -170,8 +170,12 @@ static umode_t nvme_hwmon_is_visible(const void *_data,
 	case hwmon_temp_max:
 	case hwmon_temp_min:
 		if ((!channel && data->ctrl->wctemp) ||
-		    (channel && data->log.temp_sensor[channel - 1]))
+		    (channel && data->log.temp_sensor[channel - 1])) {
+			if (data->ctrl->quirks &
+			    NVME_QUIRK_NO_TEMP_THRESH_CHANGE)
+				return 0444;
 			return 0644;
+		}
 		break;
 	case hwmon_temp_alarm:
 		if (!channel)
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 000a3d9..19e5e87 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -115,6 +115,11 @@ enum nvme_quirks {
 	 * Prevent tag overlap between queues
 	 */
 	NVME_QUIRK_SHARED_TAGS                  = (1 << 13),
+
+	/*
+	 * Don't change the value of the temperature threshold feature
+	 */
+	NVME_QUIRK_NO_TEMP_THRESH_CHANGE	= (1 << 14),
 };
 
 /*
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 931d4a9..2c0206b 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -3529,7 +3529,8 @@ static const struct pci_device_id nvme_id_table[] = {
 				NVME_QUIRK_DEALLOCATE_ZEROES, },
 	{ PCI_VDEVICE(INTEL, 0xf1a5),	/* Intel 600P/P3100 */
 		.driver_data = NVME_QUIRK_NO_DEEPEST_PS |
-				NVME_QUIRK_MEDIUM_PRIO_SQ },
+				NVME_QUIRK_MEDIUM_PRIO_SQ |
+				NVME_QUIRK_NO_TEMP_THRESH_CHANGE },
 	{ PCI_VDEVICE(INTEL, 0xf1a6),	/* Intel 760p/Pro 7600p */
 		.driver_data = NVME_QUIRK_IGNORE_DEV_SUBNQN, },
 	{ PCI_VDEVICE(INTEL, 0x5845),	/* Qemu emulated controller */
-- 
2.7.4