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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 6 Dec 2017 15:42:16 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     linux-kernel@...r.kernel.org, Rui Feng <rui_feng@...lsil.com.cn>
Subject: Re: [PATCH] mfd: Fix RTS5227 (and others) powermanagement

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@...lsil.com.cn>
> > Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> 
> 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.

Happy to do it for you this time.

Be good to get at Ack from Rui before I apply it.

-- 
Lee Jones
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog