On 27/04/18 14:55, Alan Jenkins wrote:
On 27/04/18 10:16, Hans de Goede wrote:
Hi,
On 27-04-18 11:07, Alan Jenkins wrote:
On 27/04/18 09:36, Hans de Goede wrote:
Hi,
On 27-04-18 10:33, Alan Jenkins wrote:
In v4.16 I read the new Kconfig,
The code changing the LPM settings is guarded by this check:
if (link->lpm_policy != ap->target_lpm_policy)
Where link->lpm_policy always gets initialized to ATA_LPM_UNKNOWN
and ap->target_lpm_policy gets set to the Kconfig default (*) or
the value written to sysfs.
So when the policy is set to ATA_LPM_UNKNOWN we are not making
any changes,
Ah, right. That's very much what it looks like.
*) The Kconfig default only applies to chipsets which are marked as
"mobile", so this should only be used on laptops and some HTPC-ish
boxes which use a mobile chipset.
As you say, the real confusion comes from the sysfs file. In principle
it might be "fixed" by removing LPM_UNKNOWN as an option for
`ap->target_lpm_policy` in favour of "firmware_defaults"...
or minimally: not lying, showing it as a value "unknown" in sysfs,
which cannot be set at runtime. That might be nicer for testers.
Thanks again! For explaining this so patiently. And for working on
this in general. I'm 90% sure my laptop firmware doesn't set LPM. It
definitely seems a big win in powertop.[*]
Hi, I have one more question :).
I believe `medium_power_with_dipm` saves my laptop over 10% on idle. But
this doesn't happen by enabling the boot option (and hence the default
in F28 won't help either).
It looks like my chipset is commented as `ICH8M`, but unlike ICH9M this
is not marked as `board_ahci_mobile`.
Did you consider including ICH8M for this feature?
Regards
Alan
$ lspci -nn|grep SATA
00:1f.2 RAID bus controller [0104]: Intel Corporation 82801 Mobile SATA
Controller [RAID mode] [8086:282a] (rev 03)
I believe the CPU is "broadwell".
model name : Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz
stepping : 4
Dell Latitude E5450
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