On 29/03/18 12:06, Hans de Goede wrote:
Hi,
On 29-03-18 12:53, Alan Jenkins wrote:
My laptop LPM status, even after removing AC power:
$ head /sys/class/scsi_host/host*/link_power_management_policy
==> /sys/class/scsi_host/host0/link_power_management_policy <==
max_performance
==> /sys/class/scsi_host/host1/link_power_management_policy <==
max_performance
Right, because all the bugs you linked indicate you are on
Fedora 27 and Fedora 27 does not have the LPM changes, of you
did have the LPM changes you would get something other then
max_performance for the lpm policy.
So whatever problem you are seeing, it is not related to the
SATA LPM changes.
Regards,
Hans
Thanks your help ruling out ALPM. I see the commit message in v4.15 was
quite clear.
In v4.16 I read the new Kconfig, it looks the default for laptops has
changed to preserve the LPM value set by firmware. And that this
default is carried into Fedora 27 now.
$ grep MOBILE /boot/config-4.16.3-200.fc27.x86_64
CONFIG_SATA_MOBILE_LPM_POLICY=0
+ help
+ Select the Default SATA Link Power Management (LPM) policy to use
+ for mobile / laptop variants of chipsets / "South Bridges".
+
+ The value set has the following meanings:
+ 0 => Keep firmware settings
But the code doesn't seem to match. In `enum ata_lpm_policy`, 0 is
ATA_LPM_UNKNOWN (and there is no FIRMWARE value at all). I cannot write
"firmware" as an LPM value. And booting this Fedora kernel, reading the
LPM value still shows "max_performance".
Can the Kconfig help text be clarified?
Regards
Alan
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