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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Doug Berger <opendmb@gmail.com>, Tejun Heo <tj@kernel.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.9 126/293] libata: Add the AHCI_HFLAG_YES_ALPM
 flag
Thread-Topic: [PATCH AUTOSEL for 4.9 126/293] libata: Add the
 AHCI_HFLAG_YES_ALPM flag
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Date:   Mon, 9 Apr 2018 00:24:31 +0000
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From: Doug Berger <opendmb@gmail.com>

[ Upstream commit ef0da1bf767d9e557c6375c7066717eead54cb15 ]

Some hardware is capable of supporting Aggresive Link Power Management
even though it is not indicated by the Host Capability register.

This commit adds the AHCI_HFLAG_YES_ALPM flag to the AHCI library to
allow indication of this quirk when the Host Capability register is
Read Only and therefore cannot be changed.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/ata/ahci.h    | 1 +
 drivers/ata/libahci.c | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 0cc08f892fea..bd9ba1640b56 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -248,6 +248,7 @@ enum {
 	AHCI_HFLAG_MULTI_MSI		=3D 0,
 #endif
 	AHCI_HFLAG_WAKE_BEFORE_STOP	=3D (1 << 22), /* wake before DMA stop */
+	AHCI_HFLAG_YES_ALPM		=3D (1 << 23), /* force ALPM cap on */
=20
 	/* ap->flags bits */
=20
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 0d028ead99e8..e9eb98a33467 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -503,6 +503,11 @@ void ahci_save_initial_config(struct device *dev, stru=
ct ahci_host_priv *hpriv)
 		cap &=3D ~HOST_CAP_FBS;
 	}
=20
+	if (!(cap & HOST_CAP_ALPM) && (hpriv->flags & AHCI_HFLAG_YES_ALPM)) {
+		dev_info(dev, "controller can do ALPM, turning on CAP_ALPM\n");
+		cap |=3D HOST_CAP_ALPM;
+	}
+
 	if (hpriv->force_port_map && port_map !=3D hpriv->force_port_map) {
 		dev_info(dev, "forcing port_map 0x%x -> 0x%x\n",
 			 port_map, hpriv->force_port_map);
--=20
2.15.1