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Re: [PATCH] mfd: Fix RTS5227 (and others) powermanagement




Hi,

On 06-12-17 16:42, Lee Jones wrote:
On Wed, 06 Dec 2017, Hans de Goede wrote:

Hi,

On 06-12-17 12:21, Hans de Goede wrote:
Commit 8275b77a1513 ("mfd: rts5249: Add support for RTS5250S power
saving") adds powersaving support for device-ids 5249 524a and 525a.

But as a side effect it breaks ASPM support for all the other device-ids,
causing e.g. the Haswell CPU on a Lenovo T440s to not go into a higher
c-state then PC3, while previously it would go to PC7, causing the
machine to idle at 7.4W instead of 6.6W!

The problem here is the new option.dev_aspm_mode field, which only gets
explicitly initialized in the new code for the device-ids 5249 524a and
525a. Leaving the dev_aspm_mode 0 for the other device-ids.

The default dev_aspm_mode 0 is mapped to DEV_ASPM_DISABLE, but the
old behavior of calling rtsx_pci_enable_aspm() when idle and
rtsx_pci_disable_aspm() when busy happens when dev_aspm_mode ==
DEV_ASPM_DYNAMIC.

This commit changes the enum so that 0 = DEV_ASPM_DYNAMIC matching the
old default behavior, fixing the pm regression with the other device-ids.

Cc: Rui Feng <rui_feng@xxxxxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>

p.s.

2 remarks:

1. As this is a regression in 4.15, please queue this up as a fix for 4.15
    (I prioritized bisecting this, which took me a whole day to get a fix
     ready in time for 4.15).

If this is aimed at -the rcs, you should apply a Fixes: tag.

Right, I should have thought of that myself.

Happy to do it for you this time.

Thanks you.

Regards,

Hans