Subject: r8168 is needed to enter P-state: Package State 6 (pc6) on Haswell hardware

From: Ceriel Jacobs <[email-masked]>
Date: Wed, 01 Oct 2014 01:09:29 +0200

With in-kernel r8169 module, only P-state package C3 (pc3) can be 
reached when enabling ASPM.

Only after installing r8168 driver (and enabling ASPM), a Haswell 
Celeron G1820/G1840 processer will enter package C6 state (pc6).

Tested with Ubuntu kernel 3.13 x86_64
and Ubuntu mainline
Linux ubuntu14 3.17.0-999-generic #201409240305 SMP Wed Sep 24 02:07:04 
UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

I hope this gets fixed: Haswell processor entering pc6 with ASPM enabled 
and r8169 in-kernel module.

R8111GR hardware:
# lspci -nnkvv -s 03:00.0
03:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. 
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] 
(rev 11)
	Subsystem: ASRock Incorporation Motherboard (one of many) [1849:8168]
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping- SERR- FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- 
<MAbort- >SERR- <PERR- INTx-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin A routed to IRQ 27
	Region 0: I/O ports at e000 [size=256]
	Region 2: Memory at f0404000 (64-bit, non-prefetchable) [size=4K]
	Region 4: Memory at f0400000 (64-bit, prefetchable) [size=16K]
	Capabilities: [40] Power Management version 3
		Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA 
PME(D0+,D1+,D2+,D3hot+,D3cold+)
		Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
	Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
		Address: 00000000fee0100c  Data: 41e1
	Capabilities: [70] Express (v2) Endpoint, MSI 01
		DevCap:	MaxPayload 128 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
			ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
		DevCtl:	Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
			RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop-
			MaxPayload 128 bytes, MaxReadReq 4096 bytes
		DevSta:	CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr+ TransPend-
		LnkCap:	Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency 
L0s unlimited, L1 <64us
			ClockPM+ Surprise- LLActRep- BwNot-
		LnkCtl:	ASPM Disabled; RCB 64 bytes Disabled- CommClk+
			ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
		LnkSta:	Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- 
BWMgmt- ABWMgmt-
		DevCap2: Completion Timeout: Range ABCD, TimeoutDis+, LTR+, OBFF Via 
message/WAKE#
		DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF 
Disabled
		LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis-
			 Transmit Margin: Normal Operating Range, EnterModifiedCompliance- 
ComplianceSOS-
			 Compliance De-emphasis: -6dB
		LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, 
EqualizationPhase1-
			 EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
	Capabilities: [b0] MSI-X: Enable- Count=4 Masked-
		Vector table: BAR=4 offset=00000000
		PBA: BAR=4 offset=00000800
	Capabilities: [d0] Vital Product Data
		Unknown small resource type 00, will not decode more.
	Capabilities: [100 v1] Advanced Error Reporting
		UESta:	DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- 
MalfTLP- ECRC- UnsupReq- ACSViol-
		UEMsk:	DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- 
MalfTLP- ECRC- UnsupReq- ACSViol-
		UESvrt:	DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ 
MalfTLP+ ECRC- UnsupReq- ACSViol-
		CESta:	RxErr- BadTLP+ BadDLLP- Rollover- Timeout+ NonFatalErr-
		CEMsk:	RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
		AERCap:	First Error Pointer: 00, GenCap+ CGenEn- ChkCap+ ChkEn-
	Capabilities: [140 v1] Virtual Channel
		Caps:	LPEVC=0 RefClk=100ns PATEntryBits=1
		Arb:	Fixed- WRR32- WRR64- WRR128-
		Ctrl:	ArbSelect=Fixed
		Status:	InProgress-
		VC0:	Caps:	PATOffset=00 MaxTimeSlots=1 RejSnoopTrans-
			Arb:	Fixed- WRR32- WRR64- WRR128- TWRR128- WRR256-
			Ctrl:	Enable+ ID=0 ArbSelect=Fixed TC/VC=01
			Status:	NegoPending- InProgress-
	Capabilities: [160 v1] Device Serial Number <cut>
	Capabilities: [170 v1] Latency Tolerance Reporting
		Max snoop latency: 71680ns
		Max no snoop latency: 71680ns