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[1/3,SRU,OEM-B] SAUCE: ata: libahci: Correct setting of DEVSLP register

Message ID 20180713063106.12995-2-acelan.kao@canonical.com
State Accepted
Headers show
Series SATA device is not going to DEVSLP | expand

Commit Message

AceLan Kao July 13, 2018, 6:31 a.m. UTC 
From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

BugLink: https://bugs.launchpad.net/bugs/1781533

We have seen that on some platforms, SATA device never show any DEVSLP
residency. This prevent power gating of SATA IP, which prevent system
to transition to low power mode in systems with SLP_S0 aka modern
standby systems. The PHY logic is off only in DEVSLP not in slumber.
Reference:
https://www.intel.com/content/dam/www/public/us/en/documents/datasheets
/332995-skylake-i-o-platform-datasheet-volume-1.pdf
Section 28.7.6.1

Here driver is trying to do read-modify-write the devslp register. But
not resetting the bits for which this driver will modify values (DITO,
MDAT and DETO). So simply reset those bits before updating to new values.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/ata/libahci.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Aaron Ma July 13, 2018, 8:05 a.m. UTC | #1 
On 07/13/2018 02:31 PM, AceLan Kao wrote:
> From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1781533
> 
> We have seen that on some platforms, SATA device never show any DEVSLP
> residency. This prevent power gating of SATA IP, which prevent system
> to transition to low power mode in systems with SLP_S0 aka modern
> standby systems. The PHY logic is off only in DEVSLP not in slumber.
> Reference:
> https://www.intel.com/content/dam/www/public/us/en/documents/datasheets
> /332995-skylake-i-o-platform-datasheet-volume-1.pdf
> Section 28.7.6.1
> 
> Here driver is trying to do read-modify-write the devslp register. But
> not resetting the bits for which this driver will modify values (DITO,
> MDAT and DETO). So simply reset those bits before updating to new values.
> 
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Was it reviewed by rafael?
I didn't find the reply email on lkml, could you post the link?

Please add:
Link: https://patchwork.kernel.org/patch/XXX
in each commit, your signed-off too.


> ---
>  drivers/ata/libahci.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
> index a0de7a38430c..40d8dcd175e3 100644
> --- a/drivers/ata/libahci.c
> +++ b/drivers/ata/libahci.c
> @@ -2145,6 +2145,8 @@ static void ahci_set_aggressive_devslp(struct ata_port *ap, bool sleep)
>  		deto = 20;
>  	}
>  
> +	/* Make dito, mdat, deto bits to 0s */
> +	devslp &= ~GENMASK_ULL(24, 2);
>  	devslp |= ((dito << PORT_DEVSLP_DITO_OFFSET) |
>  		   (mdat << PORT_DEVSLP_MDAT_OFFSET) |
>  		   (deto << PORT_DEVSLP_DETO_OFFSET) |
> -- 2.17.1
> -- kernel-team mailing list kernel-team@lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
>
diff mbox series

Patch

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index a0de7a38430c..40d8dcd175e3 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -2145,6 +2145,8 @@  static void ahci_set_aggressive_devslp(struct ata_port *ap, bool sleep)
 		deto = 20;
 	}
 
+	/* Make dito, mdat, deto bits to 0s */
+	devslp &= ~GENMASK_ULL(24, 2);
 	devslp |= ((dito << PORT_DEVSLP_DITO_OFFSET) |
 		   (mdat << PORT_DEVSLP_MDAT_OFFSET) |
 		   (deto << PORT_DEVSLP_DETO_OFFSET) |