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

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Date:   Wed,  6 Dec 2017 12:21:35 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     Hans de Goede <hdegoede@...hat.com>, linux-kernel@...r.kernel.org,
        Rui Feng <rui_feng@...lsil.com.cn>
Subject: [PATCH] mfd: Fix RTS5227 (and others) powermanagement

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>
---
 include/linux/mfd/rtsx_pci.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mfd/rtsx_pci.h b/include/linux/mfd/rtsx_pci.h
index a2a1318a3d0c..c3d3f04d8cc6 100644
--- a/include/linux/mfd/rtsx_pci.h
+++ b/include/linux/mfd/rtsx_pci.h
@@ -915,10 +915,10 @@ enum PDEV_STAT  {PDEV_STAT_IDLE, PDEV_STAT_RUN};
 #define LTR_L1SS_PWR_GATE_CHECK_CARD_EN	BIT(6)

 enum dev_aspm_mode {
-	DEV_ASPM_DISABLE = 0,
 	DEV_ASPM_DYNAMIC,
 	DEV_ASPM_BACKDOOR,
 	DEV_ASPM_STATIC,
+	DEV_ASPM_DISABLE,
 };

 /*
-- 
2.14.3