Date:   Tue, 21 Aug 2018 09:28:21 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     Bjorn Helgaas <helgaas@...nel.org>,
        Heiner Kallweit <hkallweit1@...il.com>, jian-hong@...lessm.com
Cc:     David Miller <davem@...emloft.net>, nic_swsd@...ltek.com,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux@...lessm.com, linux-pci@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH] r8169: don't use MSI-X on RTL8106e

On 20/08/18 19:44, Bjorn Helgaas wrote:
> [+cc Marc, Thomas, Christoph, linux-pci)
> (beginning of thread at [1])
> 
> On Thu, Aug 16, 2018 at 09:50:48PM +0200, Heiner Kallweit wrote:
>> On 16.08.2018 21:39, David Miller wrote:
>>> From: Heiner Kallweit <hkallweit1@...il.com>
>>> Date: Thu, 16 Aug 2018 21:37:31 +0200
>>>
>>>> On 16.08.2018 21:21, David Miller wrote:
>>>>> From: <jian-hong@...lessm.com>
>>>>> Date: Wed, 15 Aug 2018 14:21:10 +0800
>>>>>
>>>>>> Found the ethernet network on ASUS X441UAR doesn't come back on resume
>>>>>> from suspend when using MSI-X.  The chip is RTL8106e - version 39.
>>>>>
>>>>> Heiner, please take a look at this.
>>>>>
>>>>> You recently disabled MSI-X on RTL8168g for similar reasons.
>>>>>
>>>>> Now that we've seen two chips like this, maybe there is some other
>>>>> problem afoot.
>>>>>
>>>> Thanks for the hint. I saw it already and just contacted Realtek
>>>> whether they are aware of any MSI-X issues with particular chip
>>>> versions. With the chip versions I have access to MSI-X works fine.
>>>>
>>>> There's also the theoretical option that the issues are caused by
>>>> broken BIOS's. But so far only chip versions have been reported
>>>> which are very similar, at least with regard to version number
>>>> (2x VER_40, 1x VER_39). So they may share some buggy component.
>>>>
>>>> Let's see whether Realtek can provide some hint.
>>>> If more chip versions are reported having problems with MSI-X,
>>>> then we could switch to a whitelist or disable MSI-X in general.
>>>
>>> It could be that we need to reprogram some register(s) on resume,
>>> which normally might not be needed, and that is what is causing the
>>> problem with some chips.
>>>
>> Indeed. That's what I'm checking with Realtek.
>> In the register list in the r8169 driver there's one entry which
>> seems to indicate that there are MSI-X specific settings.
>> However this register isn't used, and the r8168 vendor driver
>> uses only MSI. And there are no public datasheets.
> 
> Do we have any information about these chip versions in other systems?
> Or other devices using MSI-X in the same ASUS system?  It seems
> possible that there's some PCI core or suspend/resume issue with MSI-X
> and this patch just avoids it without fixing the root cause.
> 
> It might be useful to have a kernel.org bugzilla with the complete
> dmesg, "sudo lspci -vv" output, and /proc/interrupts contents archived
> for future reference.

The one system I have with a Realtek chip seems happy enough with MSI-X,
but it never gets suspended. There is comment in the patch that I don't
quite get:

> It is the IRQ 127 - PCI-MSI used by enp2s0.  However, lspci lists MSI is
> disabled and MSI-X is enabled which conflicts to the interrupt table.

What do you mean by "conflicts"? With what? Another question is whether
you've loaded any firmware (some versions of the Realtek HW seem to require
it).

For the posterity, some data from my own system, which I don't know if it
has any relevance to the problem at hand.

Thanks,

	M.

[    2.624963] r8169 0000:02:00.0 eth0: RTL8168g/8111g, 5a:fe:ad:ce:11:00, XID 4c000800, IRQ 26
[    2.633398] r8169 0000:02:00.0 eth0: jumbo features [frames: 9200 bytes, tx checksumming: ko]

 26:         50     997005          0          0       MSI 1048576 Edge      enp2s0

02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0c)
	Subsystem: Realtek Semiconductor Co., Ltd. RTL8111/8168 PCI Express Gigabit Ethernet controller
	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 25
	Region 0: I/O ports at 1000 [size=256]
	Region 2: Memory at 100004000 (64-bit, prefetchable) [size=4K]
	Region 4: Memory at 100000000 (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: 0000000000000000  Data: 0000
	Capabilities: [70] Express (v2) Endpoint, MSI 01
		DevCap:	MaxPayload 128 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
			ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 0.000W
		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- ASPMOptComp+
		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
pcilib: sysfs_read_vpd: read failed: Input/output error
		Not readable
	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=ff
			Status:	NegoPending- InProgress-
	Capabilities: [160 v1] Device Serial Number 00-00-00-00-00-00-00-00
	Capabilities: [170 v1] Latency Tolerance Reporting
		Max snoop latency: 0ns
		Max no snoop latency: 0ns
	Kernel driver in use: r8169


-- 
Jazz is not dead. It just smells funny...

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