[RFC PATCH v2 0/2] ata: ahci: Enable DEVSLP by default on SLP_S0 support

[RFC PATCH v2 0/2] ata: ahci: Enable DEVSLP by default on SLP_S0 support

[Srinivas Pandruvada]

One of the requirement for modern x86 system to enter lowest power mode
(SLP_S0) is SATA IP block to be off. This is true even during when
platform is suspended to idle and not only in opportunistic (runtime)
suspend.
This series is to enable DEVSLP by default.

v2
- As suggested by Hans, it is possible to have ASP with DEVSLP, so
add a new state.
- Removed usage of mem_sleep_current, instead just rely on low power
idle flag. Don't feel good to EXPORT from core suspend code.
- Depending host policy to decide if we enable DEVSLP by default.

Srinivas (1):
  ata: ahci: Enable DEVSLP by default on x86 with SLP_S0

Srinivas Pandruvada (1):
  ata: ahci: Support state with min power but Partial low power state

 drivers/ata/ahci.c        | 15 +++++++++++++++
 drivers/ata/libahci.c     |  6 +++++-
 drivers/ata/libata-core.c |  1 +
 drivers/ata/libata-scsi.c |  1 +
 include/linux/libata.h    |  3 ++-
 5 files changed, 24 insertions(+), 2 deletions(-)

-- 
2.17.1

[RFC PATCH v2 1/2] ata: ahci: Support state with min power and Partial low power state

[Srinivas Pandruvada]

Currently when min_power policy is selected, the partial low power state
is not entered and link will try aggressively enter to only slumber state.
Add a new policy which still enable DEVSLP but also try to enter partial
low power state.

For information the difference between partial and slumber
Partial – PHY logic is powered up, and in a reduced power state. The link
PM exit latency to active state maximum is 10 ns.
Slumber – PHY logic is powered up, and in a reduced power state. The link
PM exit latency to active state maximum is 10 ms.
Devslp – PHY logic is powered down. The link PM exit latency from this
state to active state maximum is 20 ms, unless otherwise specified by
DETO.

Suggested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/ata/libahci.c     | 6 +++++-
 drivers/ata/libata-core.c | 1 +
 drivers/ata/libata-scsi.c | 1 +
 include/linux/libata.h    | 3 ++-
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 511fb67f363d..8cf2cf49537d 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -799,8 +799,11 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
 				return 0;
 		} else {
 			cmd |= PORT_CMD_ALPE;
+
 			if (policy == ATA_LPM_MIN_POWER)
 				cmd |= PORT_CMD_ASP;
+			else if (policy == ATA_LPM_MIN_POWER_WITH_ASP)
+				cmd &= ~PORT_CMD_ASP;
 
 			/* write out new cmd value */
 			writel(cmd, port_mmio + PORT_CMD);
@@ -811,7 +814,8 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
 	if ((hpriv->cap2 & HOST_CAP2_SDS) &&
 	    (hpriv->cap2 & HOST_CAP2_SADM) &&
 	    (link->device->flags & ATA_DFLAG_DEVSLP)) {
-		if (policy == ATA_LPM_MIN_POWER)
+		if (policy == ATA_LPM_MIN_POWER ||
+		    policy == ATA_LPM_MIN_POWER_WITH_ASP)
 			ahci_set_aggressive_devslp(ap, true);
 		else
 			ahci_set_aggressive_devslp(ap, false);
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index cc71c63df381..245a59e6cb18 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3970,6 +3970,7 @@ int sata_link_scr_lpm(struct ata_link *link, enum ata_lpm_policy policy,
 		scontrol |= (0x6 << 8);
 		break;
 	case ATA_LPM_MED_POWER_WITH_DIPM:
+	case ATA_LPM_MIN_POWER_WITH_ASP:
 	case ATA_LPM_MIN_POWER:
 		if (ata_link_nr_enabled(link) > 0)
 			/* no restrictions on LPM transitions */
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index aad1b01447de..2d683db50ceb 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -110,6 +110,7 @@ static const char *ata_lpm_policy_names[] = {
 	[ATA_LPM_MAX_POWER]		= "max_performance",
 	[ATA_LPM_MED_POWER]		= "medium_power",
 	[ATA_LPM_MED_POWER_WITH_DIPM]	= "med_power_with_dipm",
+	[ATA_LPM_MIN_POWER_WITH_ASP]	= "min_power_with_asp",
 	[ATA_LPM_MIN_POWER]		= "min_power",
 };
 
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 32f247cb5e9e..1e154f1f7e8f 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -523,7 +523,8 @@ enum ata_lpm_policy {
 	ATA_LPM_MAX_POWER,
 	ATA_LPM_MED_POWER,
 	ATA_LPM_MED_POWER_WITH_DIPM, /* Med power + DIPM as win IRST does */
-	ATA_LPM_MIN_POWER,
+	ATA_LPM_MIN_POWER_WITH_ASP, /* Min Power + partial and slumber */
+	ATA_LPM_MIN_POWER, /* Min power + no partial (slumber only) */
 };
 
 enum ata_lpm_hints {
-- 
2.17.1

[RFC PATCH v2 2/2] ata: ahci: Enable DEVSLP by default on x86 with SLP_S0

[Srinivas Pandruvada]

From: Srinivas <srinivas.pandruvada@linux.intel.com>

One of the requirement for modern x86 system to enter lowest power mode
(SLP_S0) is SATA IP block to be off. This is true even during when
platform is suspended to idle and not only in opportunistic (runtime)
suspend.

Several of these system don't have traditional ACPI S3, so it is
important that they enter SLP_S0 state, to avoid draining battery even
during suspend. So it is important that out of the box Linux installation
reach this state.

SATA IP block doesn't get turned off till SATA is in DEVSLP mode. Here
user has to either use scsi-host sysfs or tools like powertop to set
the sata-host link_power_management_policy to min_power.

This change sets by default link power management policy to min_power
with partial (preferred) or slumber support on idle for some platforms.
To avoid regressions, the following conditions are used:
- The kernel config is already set to use med_power_with_dipm or deeper
- System is a SLP_S0 capable using ACPI low power idle flag
This combination will make sure that systems are fairly recent and
since getting shipped with SLP_S0 support, the DEVSLP function
is already validated.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/ata/ahci.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index b2b9eba1d214..e8d425823f9b 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1604,6 +1604,19 @@ static int ahci_init_msi(struct pci_dev *pdev, unsigned int n_ports,
 	return pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX);
 }
 
+static void ahci_update_mobile_policy(struct ahci_host_priv *hpriv)
+{
+#ifdef CONFIG_ACPI
+	if (mobile_lpm_policy > ATA_LPM_MED_POWER &&
+	    (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) {
+		if (hpriv->cap & HOST_CAP_PART)
+			mobile_lpm_policy = ATA_LPM_MIN_POWER_WITH_ASP;
+		else if (hpriv->cap & HOST_CAP_SSC)
+			mobile_lpm_policy = ATA_LPM_MIN_POWER;
+	}
+#endif
+}
+
 static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	unsigned int board_id = ent->driver_data;
@@ -1796,6 +1809,8 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (pi.flags & ATA_FLAG_EM)
 		ahci_reset_em(host);
 
+	ahci_update_mobile_policy(hpriv);
+
 	for (i = 0; i < host->n_ports; i++) {
 		struct ata_port *ap = host->ports[i];
 
-- 
2.17.1

Re: [RFC PATCH v2 1/2] ata: ahci: Support state with min power and Partial low power state

[Hans de Goede]

Hi,

On 13-07-18 00:27, Srinivas Pandruvada wrote:
> Currently when min_power policy is selected, the partial low power state
> is not entered and link will try aggressively enter to only slumber state.
> Add a new policy which still enable DEVSLP but also try to enter partial
> low power state.
> 
> For information the difference between partial and slumber
> Partial – PHY logic is powered up, and in a reduced power state. The link
> PM exit latency to active state maximum is 10 ns.
> Slumber – PHY logic is powered up, and in a reduced power state. The link
> PM exit latency to active state maximum is 10 ms.
> Devslp – PHY logic is powered down. The link PM exit latency from this
> state to active state maximum is 20 ms, unless otherwise specified by
> DETO.
> 
> Suggested-by: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

You got this the wrong way around, when ALP is not set you only get
partial, the ALP bit is active high, not active low as your commit
suggests.  So the name of the new policy should be min_power_without_asp.

Regards,

Hans






> ---
>   drivers/ata/libahci.c     | 6 +++++-
>   drivers/ata/libata-core.c | 1 +
>   drivers/ata/libata-scsi.c | 1 +
>   include/linux/libata.h    | 3 ++-
>   4 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
> index 511fb67f363d..8cf2cf49537d 100644
> --- a/drivers/ata/libahci.c
> +++ b/drivers/ata/libahci.c
> @@ -799,8 +799,11 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
>   				return 0;
>   		} else {
>   			cmd |= PORT_CMD_ALPE;
> +
>   			if (policy == ATA_LPM_MIN_POWER)
>   				cmd |= PORT_CMD_ASP;
> +			else if (policy == ATA_LPM_MIN_POWER_WITH_ASP)
> +				cmd &= ~PORT_CMD_ASP;
>   
>   			/* write out new cmd value */
>   			writel(cmd, port_mmio + PORT_CMD);
> @@ -811,7 +814,8 @@ static int ahci_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
>   	if ((hpriv->cap2 & HOST_CAP2_SDS) &&
>   	    (hpriv->cap2 & HOST_CAP2_SADM) &&
>   	    (link->device->flags & ATA_DFLAG_DEVSLP)) {
> -		if (policy == ATA_LPM_MIN_POWER)
> +		if (policy == ATA_LPM_MIN_POWER ||
> +		    policy == ATA_LPM_MIN_POWER_WITH_ASP)
>   			ahci_set_aggressive_devslp(ap, true);
>   		else
>   			ahci_set_aggressive_devslp(ap, false);
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index cc71c63df381..245a59e6cb18 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -3970,6 +3970,7 @@ int sata_link_scr_lpm(struct ata_link *link, enum ata_lpm_policy policy,
>   		scontrol |= (0x6 << 8);
>   		break;
>   	case ATA_LPM_MED_POWER_WITH_DIPM:
> +	case ATA_LPM_MIN_POWER_WITH_ASP:
>   	case ATA_LPM_MIN_POWER:
>   		if (ata_link_nr_enabled(link) > 0)
>   			/* no restrictions on LPM transitions */
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index aad1b01447de..2d683db50ceb 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -110,6 +110,7 @@ static const char *ata_lpm_policy_names[] = {
>   	[ATA_LPM_MAX_POWER]		= "max_performance",
>   	[ATA_LPM_MED_POWER]		= "medium_power",
>   	[ATA_LPM_MED_POWER_WITH_DIPM]	= "med_power_with_dipm",
> +	[ATA_LPM_MIN_POWER_WITH_ASP]	= "min_power_with_asp",
>   	[ATA_LPM_MIN_POWER]		= "min_power",
>   };
>   
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 32f247cb5e9e..1e154f1f7e8f 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -523,7 +523,8 @@ enum ata_lpm_policy {
>   	ATA_LPM_MAX_POWER,
>   	ATA_LPM_MED_POWER,
>   	ATA_LPM_MED_POWER_WITH_DIPM, /* Med power + DIPM as win IRST does */
> -	ATA_LPM_MIN_POWER,
> +	ATA_LPM_MIN_POWER_WITH_ASP, /* Min Power + partial and slumber */
> +	ATA_LPM_MIN_POWER, /* Min power + no partial (slumber only) */
>   };
>   
>   enum ata_lpm_hints {
> 

Re: [RFC PATCH v2 2/2] ata: ahci: Enable DEVSLP by default on x86 with SLP_S0

[Hans de Goede]

Hi,

On 13-07-18 00:27, Srinivas Pandruvada wrote:
> From: Srinivas <srinivas.pandruvada@linux.intel.com>
> 
> One of the requirement for modern x86 system to enter lowest power mode
> (SLP_S0) is SATA IP block to be off. This is true even during when
> platform is suspended to idle and not only in opportunistic (runtime)
> suspend.
> 
> Several of these system don't have traditional ACPI S3, so it is
> important that they enter SLP_S0 state, to avoid draining battery even
> during suspend. So it is important that out of the box Linux installation
> reach this state.
> 
> SATA IP block doesn't get turned off till SATA is in DEVSLP mode. Here
> user has to either use scsi-host sysfs or tools like powertop to set
> the sata-host link_power_management_policy to min_power.
> 
> This change sets by default link power management policy to min_power
> with partial (preferred) or slumber support on idle for some platforms.
> To avoid regressions, the following conditions are used:
> - The kernel config is already set to use med_power_with_dipm or deeper
> - System is a SLP_S0 capable using ACPI low power idle flag
> This combination will make sure that systems are fairly recent and
> since getting shipped with SLP_S0 support, the DEVSLP function
> is already validated.
> 
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> ---
>   drivers/ata/ahci.c | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
> index b2b9eba1d214..e8d425823f9b 100644
> --- a/drivers/ata/ahci.c
> +++ b/drivers/ata/ahci.c
> @@ -1604,6 +1604,19 @@ static int ahci_init_msi(struct pci_dev *pdev, unsigned int n_ports,
>   	return pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX);
>   }
>   
> +static void ahci_update_mobile_policy(struct ahci_host_priv *hpriv)
> +{
> +#ifdef CONFIG_ACPI
> +	if (mobile_lpm_policy > ATA_LPM_MED_POWER &&
> +	    (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) {
> +		if (hpriv->cap & HOST_CAP_PART)
> +			mobile_lpm_policy = ATA_LPM_MIN_POWER_WITH_ASP;
> +		else if (hpriv->cap & HOST_CAP_SSC)
> +			mobile_lpm_policy = ATA_LPM_MIN_POWER;

You are checking hpriv flags here and changing global state based on that.

Instead it would be better to add a new:

int ahci_get_initial_lpm_policy(struct ahci_host_priv *hpriv);

Function and replace this:

                 if ((hpriv->flags & AHCI_HFLAG_IS_MOBILE) &&
                     mobile_lpm_policy >= ATA_LPM_UNKNOWN &&
                     mobile_lpm_policy <= ATA_LPM_MIN_POWER)
                         ap->target_lpm_policy = mobile_lpm_policy;

With:

		ap->target_lpm_policy = ahci_get_initial_lpm_policy(priv);

And do the original checks + your new checks all in the
ahci_get_initial_lpm_policy() function.

Regards,

Hans



> +	}
> +#endif
> +}
> +
>   static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>   {
>   	unsigned int board_id = ent->driver_data;
> @@ -1796,6 +1809,8 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>   	if (pi.flags & ATA_FLAG_EM)
>   		ahci_reset_em(host);
>   
> +	ahci_update_mobile_policy(hpriv);
> +
>   	for (i = 0; i < host->n_ports; i++) {
>   		struct ata_port *ap = host->ports[i];
>   
> 

Re: [RFC PATCH v2 1/2] ata: ahci: Support state with min power and Partial low power state

[Srinivas Pandruvada]

Hi Hans,
On Fri, 2018-07-13 at 11:08 +0200, Hans de Goede wrote:
> Hi,
> 
> On 13-07-18 00:27, Srinivas Pandruvada wrote:
> > Currently when min_power policy is selected, the partial low power
> > state
> > is not entered and link will try aggressively enter to only slumber
> > state.
> > Add a new policy which still enable DEVSLP but also try to enter
> > partial
> > low power state.
> > 
> > For information the difference between partial and slumber
> > Partial – PHY logic is powered up, and in a reduced power state.
> > The link
> > PM exit latency to active state maximum is 10 ns.
> > Slumber – PHY logic is powered up, and in a reduced power state.
> > The link
> > PM exit latency to active state maximum is 10 ms.
> > Devslp – PHY logic is powered down. The link PM exit latency from
> > this
> > state to active state maximum is 20 ms, unless otherwise specified
> > by
> > DETO.
> > 
> > Suggested-by: Hans de Goede <hdegoede@redhat.com>
> > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel
> > .com>
> 
> You got this the wrong way around, when ALP
You mean ASP, as per spec in section 3.3.7 of the spec.

>  is not set you only get
> partial,
Not exactly.
It means that the system will try to enter aggressively  partial . I
have seen slumber residency also when this is reset. When "set" you
don't see any any partial. But when you reset you see both. So based on
idle duration link will transition from partial to slumber even if "not
set".

> the ALP bit is active high, not active low as your commit
> suggests.  So the name of the new policy should be
> min_power_without_asp.


The policy name I am suggesting is not the actual bit value of ASP (I
interpreted ASP as name for partial), but whether you will get to
partial or not. So I think it is better to rename to
"min_power_with_partial". User should not have to worry about the bit
value. 


So user will see with the rename from "min_power_with_asp" to
"min_power_with_partial":

#cat /sys/class/scsi_host/host*/link_power_management_policy 
min_power_with_partial
min_power_with_partial
min_power_with_partial

Output of test (You will see both partial and slumber)

SATA LPM Summary - Sampled: Residency (Percentage)
Disk Name          , Off (%), Active (%), Partial (%), Slumber (%),
Devsleep (%), Other (%), Uninitialized (%)
---------          , -------, ----------, -----------, -----------, -
-----------, ---------, -----------------
INTEL SSDSCKJF180A5, 0.0    , 4.6       , 13.1       , 30.3       ,
52.0        , 0.0      , 0.0

SATA LPM Summary - Sampled: Counts
Disk Name          , Off, Active, Partial, Slumber, Devsleep, Other,
Uninitialized
---------          , ---, ------, -------, -------, --------, -----, --
-----------
INTEL SSDSCKJF180A5, 0  , 9     , 27     , 60     , 103     , 0    , 0


# cat /sys/class/scsi_host/host*/link_power_management_policy
min_power
min_power
min_power

Output of test (You will see only slumber)

SATA LPM Summary - Sampled: Residency (Percentage)
Disk Name          , Off (%), Active (%), Partial (%), Slumber (%),
Devsleep (%), Other (%), Uninitialized (%)
---------          , -------, ----------, -----------, -----------, -
-----------, ---------, -----------------
INTEL SSDSCKJF180A5, 0.0    , 6.8       , 0.0        , 53.8       ,
39.3        , 0.0      , 0.0

SATA LPM Summary - Sampled: Counts
Disk Name          , Off, Active, Partial, Slumber, Devsleep, Other,
Uninitialized
---------          , ---, ------, -------, -------, --------, -----, --
-----------
INTEL SSDSCKJF180A5, 0  , 11    , 0      , 107    , 76      , 0    , 0

Thanks,
Srinivas

> 
> Regards,
> 
> Hans
> 
> 
> 
> 
> 
> 
> > ---
> >   drivers/ata/libahci.c     | 6 +++++-
> >   drivers/ata/libata-core.c | 1 +
> >   drivers/ata/libata-scsi.c | 1 +
> >   include/linux/libata.h    | 3 ++-
> >   4 files changed, 9 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
> > index 511fb67f363d..8cf2cf49537d 100644
> > --- a/drivers/ata/libahci.c
> > +++ b/drivers/ata/libahci.c
> > @@ -799,8 +799,11 @@ static int ahci_set_lpm(struct ata_link *link,
> > enum ata_lpm_policy policy,
> >   				return 0;
> >   		} else {
> >   			cmd |= PORT_CMD_ALPE;
> > +
> >   			if (policy == ATA_LPM_MIN_POWER)
> >   				cmd |= PORT_CMD_ASP;
> > +			else if (policy ==
> > ATA_LPM_MIN_POWER_WITH_ASP)
> > +				cmd &= ~PORT_CMD_ASP;
> >   
> >   			/* write out new cmd value */
> >   			writel(cmd, port_mmio + PORT_CMD);
> > @@ -811,7 +814,8 @@ static int ahci_set_lpm(struct ata_link *link,
> > enum ata_lpm_policy policy,
> >   	if ((hpriv->cap2 & HOST_CAP2_SDS) &&
> >   	    (hpriv->cap2 & HOST_CAP2_SADM) &&
> >   	    (link->device->flags & ATA_DFLAG_DEVSLP)) {
> > -		if (policy == ATA_LPM_MIN_POWER)
> > +		if (policy == ATA_LPM_MIN_POWER ||
> > +		    policy == ATA_LPM_MIN_POWER_WITH_ASP)
> >   			ahci_set_aggressive_devslp(ap, true);
> >   		else
> >   			ahci_set_aggressive_devslp(ap, false);
> > diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> > index cc71c63df381..245a59e6cb18 100644
> > --- a/drivers/ata/libata-core.c
> > +++ b/drivers/ata/libata-core.c
> > @@ -3970,6 +3970,7 @@ int sata_link_scr_lpm(struct ata_link *link,
> > enum ata_lpm_policy policy,
> >   		scontrol |= (0x6 << 8);
> >   		break;
> >   	case ATA_LPM_MED_POWER_WITH_DIPM:
> > +	case ATA_LPM_MIN_POWER_WITH_ASP:
> >   	case ATA_LPM_MIN_POWER:
> >   		if (ata_link_nr_enabled(link) > 0)
> >   			/* no restrictions on LPM transitions */
> > diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> > index aad1b01447de..2d683db50ceb 100644
> > --- a/drivers/ata/libata-scsi.c
> > +++ b/drivers/ata/libata-scsi.c
> > @@ -110,6 +110,7 @@ static const char *ata_lpm_policy_names[] = {
> >   	[ATA_LPM_MAX_POWER]		= "max_performance",
> >   	[ATA_LPM_MED_POWER]		= "medium_power",
> >   	[ATA_LPM_MED_POWER_WITH_DIPM]	=
> > "med_power_with_dipm",
> > +	[ATA_LPM_MIN_POWER_WITH_ASP]	=
> > "min_power_with_asp",
> >   	[ATA_LPM_MIN_POWER]		= "min_power",
> >   };
> >   
> > diff --git a/include/linux/libata.h b/include/linux/libata.h
> > index 32f247cb5e9e..1e154f1f7e8f 100644
> > --- a/include/linux/libata.h
> > +++ b/include/linux/libata.h
> > @@ -523,7 +523,8 @@ enum ata_lpm_policy {
> >   	ATA_LPM_MAX_POWER,
> >   	ATA_LPM_MED_POWER,
> >   	ATA_LPM_MED_POWER_WITH_DIPM, /* Med power + DIPM as win
> > IRST does */
> > -	ATA_LPM_MIN_POWER,
> > +	ATA_LPM_MIN_POWER_WITH_ASP, /* Min Power + partial and
> > slumber */
> > +	ATA_LPM_MIN_POWER, /* Min power + no partial (slumber
> > only) */
> >   };
> >   
> >   enum ata_lpm_hints {
> > 

Re: [RFC PATCH v2 1/2] ata: ahci: Support state with min power and Partial low power state

[Hans de Goede]

Hi,

On 13-07-18 17:06, Srinivas Pandruvada wrote:
> Hi Hans,
> On Fri, 2018-07-13 at 11:08 +0200, Hans de Goede wrote:
>> Hi,
>>
>> On 13-07-18 00:27, Srinivas Pandruvada wrote:
>>> Currently when min_power policy is selected, the partial low power
>>> state
>>> is not entered and link will try aggressively enter to only slumber
>>> state.
>>> Add a new policy which still enable DEVSLP but also try to enter
>>> partial
>>> low power state.
>>>
>>> For information the difference between partial and slumber
>>> Partial – PHY logic is powered up, and in a reduced power state.
>>> The link
>>> PM exit latency to active state maximum is 10 ns.
>>> Slumber – PHY logic is powered up, and in a reduced power state.
>>> The link
>>> PM exit latency to active state maximum is 10 ms.
>>> Devslp – PHY logic is powered down. The link PM exit latency from
>>> this
>>> state to active state maximum is 20 ms, unless otherwise specified
>>> by
>>> DETO.
>>>
>>> Suggested-by: Hans de Goede <hdegoede@redhat.com>
>>> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel
>>> .com>
>>
>> You got this the wrong way around, when ALP
> You mean ASP, as per spec in section 3.3.7 of the spec.
> 
>>   is not set you only get
>> partial,
> Not exactly.
> It means that the system will try to enter aggressively  partial . I
> have seen slumber residency also when this is reset. When "set" you
> don't see any any partial. But when you reset you see both. So based on
> idle duration link will transition from partial to slumber even if "not
> set".
> 
>> the ALP bit is active high, not active low as your commit
>> suggests.  So the name of the new policy should be
>> min_power_without_asp.
> 
> 
> The policy name I am suggesting is not the actual bit value of ASP (I
> interpreted ASP as name for partial), but whether you will get to
> partial or not. So I think it is better to rename to
> "min_power_with_partial". User should not have to worry about the bit
> value.
> 
> 
> So user will see with the rename from "min_power_with_asp" to
> "min_power_with_partial":
> 
> #cat /sys/class/scsi_host/host*/link_power_management_policy
> min_power_with_partial
> min_power_with_partial
> min_power_with_partial
> 
> Output of test (You will see both partial and slumber)
> 
> SATA LPM Summary - Sampled: Residency (Percentage)
> Disk Name          , Off (%), Active (%), Partial (%), Slumber (%), Devsleep (%), Other (%), Uninitialized (%)
> ---------          , -------, ----------, -----------, -----------, ------------, ---------, -----------------
> INTEL SSDSCKJF180A5, 0.0    , 4.6       , 13.1       , 30.3       , 52.0        , 0.0      , 0.0
> 
> SATA LPM Summary - Sampled: Counts
> Disk Name          , Off, Active, Partial, Slumber, Devsleep, Other, Uninitialized
> ---------          , ---, ------, -------, -------, --------, -----, -------------
> INTEL SSDSCKJF180A5, 0  , 9     , 27     , 60     , 103     , 0    , 0
> 
> 
> # cat /sys/class/scsi_host/host*/link_power_management_policy
> min_power
> min_power
> min_power
> 
> Output of test (You will see only slumber)
> 
> SATA LPM Summary - Sampled: Residency (Percentage)
> Disk Name          , Off (%), Active (%), Partial (%), Slumber (%), Devsleep (%), Other (%), Uninitialized (%)
> ---------          , -------, ----------, -----------, -----------, ------------, ---------, -----------------
> INTEL SSDSCKJF180A5, 0.0    , 6.8       , 0.0        , 53.8       , 39.3        , 0.0      , 0.0
> 
> SATA LPM Summary - Sampled: Counts
> Disk Name          , Off, Active, Partial, Slumber, Devsleep, Other, Uninitialized
> ---------          , ---, ------, -------, -------, --------, -----, -------------
> INTEL SSDSCKJF180A5, 0  , 11    , 0      , 107    , 76      , 0    , 0

Ah, I see thank you for clarifying that. Yes I agree that
min_power_with_partial is the best name for the new policy.

For the next version do not forget to make the overriding of the
lpm policy a per host thing, rather then directly overriding the
global value as I mentioned in a previous mail.

One other thing is to NOT override the policy if it is set on
the kernel-commandline, which I believe will require setting the
global value to -1 and only set another value if the global value
is not -1 (using you settings where applicable and falling back
to CONFIG_SATA_MOBILE_LPM_POLICY where not applicable).

Regards,

Hans


>>> ---
>>>    drivers/ata/libahci.c     | 6 +++++-
>>>    drivers/ata/libata-core.c | 1 +
>>>    drivers/ata/libata-scsi.c | 1 +
>>>    include/linux/libata.h    | 3 ++-
>>>    4 files changed, 9 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
>>> index 511fb67f363d..8cf2cf49537d 100644
>>> --- a/drivers/ata/libahci.c
>>> +++ b/drivers/ata/libahci.c
>>> @@ -799,8 +799,11 @@ static int ahci_set_lpm(struct ata_link *link,
>>> enum ata_lpm_policy policy,
>>>    				return 0;
>>>    		} else {
>>>    			cmd |= PORT_CMD_ALPE;
>>> +
>>>    			if (policy == ATA_LPM_MIN_POWER)
>>>    				cmd |= PORT_CMD_ASP;
>>> +			else if (policy ==
>>> ATA_LPM_MIN_POWER_WITH_ASP)
>>> +				cmd &= ~PORT_CMD_ASP;
>>>    
>>>    			/* write out new cmd value */
>>>    			writel(cmd, port_mmio + PORT_CMD);
>>> @@ -811,7 +814,8 @@ static int ahci_set_lpm(struct ata_link *link,
>>> enum ata_lpm_policy policy,
>>>    	if ((hpriv->cap2 & HOST_CAP2_SDS) &&
>>>    	    (hpriv->cap2 & HOST_CAP2_SADM) &&
>>>    	    (link->device->flags & ATA_DFLAG_DEVSLP)) {
>>> -		if (policy == ATA_LPM_MIN_POWER)
>>> +		if (policy == ATA_LPM_MIN_POWER ||
>>> +		    policy == ATA_LPM_MIN_POWER_WITH_ASP)
>>>    			ahci_set_aggressive_devslp(ap, true);
>>>    		else
>>>    			ahci_set_aggressive_devslp(ap, false);
>>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>>> index cc71c63df381..245a59e6cb18 100644
>>> --- a/drivers/ata/libata-core.c
>>> +++ b/drivers/ata/libata-core.c
>>> @@ -3970,6 +3970,7 @@ int sata_link_scr_lpm(struct ata_link *link,
>>> enum ata_lpm_policy policy,
>>>    		scontrol |= (0x6 << 8);
>>>    		break;
>>>    	case ATA_LPM_MED_POWER_WITH_DIPM:
>>> +	case ATA_LPM_MIN_POWER_WITH_ASP:
>>>    	case ATA_LPM_MIN_POWER:
>>>    		if (ata_link_nr_enabled(link) > 0)
>>>    			/* no restrictions on LPM transitions */
>>> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
>>> index aad1b01447de..2d683db50ceb 100644
>>> --- a/drivers/ata/libata-scsi.c
>>> +++ b/drivers/ata/libata-scsi.c
>>> @@ -110,6 +110,7 @@ static const char *ata_lpm_policy_names[] = {
>>>    	[ATA_LPM_MAX_POWER]		= "max_performance",
>>>    	[ATA_LPM_MED_POWER]		= "medium_power",
>>>    	[ATA_LPM_MED_POWER_WITH_DIPM]	=
>>> "med_power_with_dipm",
>>> +	[ATA_LPM_MIN_POWER_WITH_ASP]	=
>>> "min_power_with_asp",
>>>    	[ATA_LPM_MIN_POWER]		= "min_power",
>>>    };
>>>    
>>> diff --git a/include/linux/libata.h b/include/linux/libata.h
>>> index 32f247cb5e9e..1e154f1f7e8f 100644
>>> --- a/include/linux/libata.h
>>> +++ b/include/linux/libata.h
>>> @@ -523,7 +523,8 @@ enum ata_lpm_policy {
>>>    	ATA_LPM_MAX_POWER,
>>>    	ATA_LPM_MED_POWER,
>>>    	ATA_LPM_MED_POWER_WITH_DIPM, /* Med power + DIPM as win
>>> IRST does */
>>> -	ATA_LPM_MIN_POWER,
>>> +	ATA_LPM_MIN_POWER_WITH_ASP, /* Min Power + partial and
>>> slumber */
>>> +	ATA_LPM_MIN_POWER, /* Min power + no partial (slumber
>>> only) */
>>>    };
>>>    
>>>    enum ata_lpm_hints {
>>>