[PATCH 3.18 44/85] libata: Drop SanDisk SD7UB3Q*G1001 NOLPM quirk

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hans de Goede <hdegoede@xxxxxxxxxx>

commit 2cfce3a86b64b53f0a70e92a6a659c720c319b45 upstream.

Commit 184add2ca23c ("libata: Apply NOLPM quirk for SanDisk
SD7UB3Q*G1001 SSDs") disabled LPM for SanDisk SD7UB3Q*G1001 SSDs.

This has lead to several reports of users of that SSD where LPM
was working fine and who know have a significantly increased idle
power consumption on their laptops.

Likely there is another problem on the T450s from the original
reporter which gets exposed by the uncore reaching deeper sleep
states (higher PC-states) due to LPM being enabled. The problem as
reported, a hardfreeze about once a day, already did not sound like
it would be caused by LPM and the reports of the SSD working fine
confirm this. The original reporter is ok with dropping the quirk.

A X250 user has reported the same hard freeze problem and for him
the problem went away after unrelated updates, I suspect some GPU
driver stack changes fixed things.

TL;DR: The original reporters problem were triggered by LPM but not
an LPM issue, so drop the quirk for the SSD in question.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1583207
Cc: stable@xxxxxxxxxxxxxxx
Cc: Richard W.M. Jones <rjones@xxxxxxxxxx>
Cc: Lorenzo Dalrio <lorenzo.dalrio@xxxxxxxxx>
Reported-by: Lorenzo Dalrio <lorenzo.dalrio@xxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Acked-by: "Richard W.M. Jones" <rjones@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/ata/libata-core.c |    3 ---
 1 file changed, 3 deletions(-)

--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4248,9 +4248,6 @@ static const struct ata_blacklist_entry
 						ATA_HORKAGE_ZERO_AFTER_TRIM |
 						ATA_HORKAGE_NOLPM, },
 
-	/* Sandisk devices which are known to not handle LPM well */
-	{ "SanDisk SD7UB3Q*G1001",	NULL,	ATA_HORKAGE_NOLPM, },
-
 	/* devices that don't properly handle queued TRIM commands */
 	{ "Micron_M500_*",		NULL,	ATA_HORKAGE_NO_NCQ_TRIM |
 						ATA_HORKAGE_ZERO_AFTER_TRIM, },