On Tue, 2018-07-17 at 11:26 +0800, AceLan Kao wrote: > Tested-by: AceLan Kao <acelan.kao@xxxxxxxxxxxxx> Thanks Kao for the test. -Srinivas > > The patches help the power consumption a little bit on my test > system, > and no obvious issue I can observe. > > 2018-07-03 3:01 GMT+08:00 Srinivas Pandruvada <srinivas.pandruvada@li > nux.intel.com>: > > 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/datash > > eets > > /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@xxxxxxxxx> > > --- > > drivers/ata/libahci.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c > > index 965842a08743..f6795d261869 100644 > > --- a/drivers/ata/libahci.c > > +++ b/drivers/ata/libahci.c > > @@ -2159,6 +2159,8 @@ 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 > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
