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Groups > linux.kernel > #1672149

[PATCH 1/3] libata: Add the AHCI_HFLAG_YES_ALPM flag

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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>
---
 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 30f67a1a4f54..ee176e4af97a 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -248,6 +248,7 @@ enum {
 	AHCI_HFLAG_MULTI_MSI		= 0,
 #endif
 	AHCI_HFLAG_WAKE_BEFORE_STOP	= (1 << 22), /* wake before DMA stop */
+	AHCI_HFLAG_YES_ALPM		= (1 << 23), /* force ALPM cap on */
 
 	/* ap->flags bits */
 
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index b3a685ad9b87..4462f8a8cf2c 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -504,6 +504,11 @@ void ahci_save_initial_config(struct device *dev, struct ahci_host_priv *hpriv)
 		cap &= ~HOST_CAP_FBS;
 	}
 
+	if (!(cap & HOST_CAP_ALPM) && (hpriv->flags & AHCI_HFLAG_YES_ALPM)) {
+		dev_info(dev, "controller can do ALPM, turning on CAP_ALPM\n");
+		cap |= HOST_CAP_ALPM;
+	}
+
 	if (hpriv->force_port_map && port_map != hpriv->force_port_map) {
 		dev_info(dev, "forcing port_map 0x%x -> 0x%x\n",
 			 port_map, hpriv->force_port_map);
-- 
2.13.0

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[PATCH 0/3] libata: prevent writes to read-only registers Doug Berger <opendmb@gmail.com> - 2017-06-22 01:30 +0200
  [PATCH 1/3] libata: Add the AHCI_HFLAG_YES_ALPM flag Doug Berger <opendmb@gmail.com> - 2017-06-22 01:30 +0200
  [PATCH 2/3] libata: Add the AHCI_HFLAG_NO_WRITE_TO_RO flag Doug Berger <opendmb@gmail.com> - 2017-06-22 01:30 +0200
  Re: [PATCH 0/3] libata: prevent writes to read-only registers Tejun Heo <tj@kernel.org> - 2017-06-22 22:20 +0200

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