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

[Aaron Ma]

On 07/13/2018 02:31 PM, AceLan Kao wrote:
> From: Srinivas Pandruvada <srinivas.pandruvada at 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 at linux.intel.com>
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki at 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 at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
>