On 7/4/2017 6:25 PM, Sinan Kaya wrote:
> On 7/4/2017 1:59 PM, Wim ten Have wrote:
>> On Tue, 4 Jul 2017 11:57:37 -0400
>> Sinan Kaya <okaya@codeaurora.org> wrote:
>>
>>> Hi,
>>>
>>> On 7/4/2017 11:32 AM, Bjorn Helgaas wrote:
>>>> [+cc linux-pci]
>>>>
>>>> Thanks very much for the detailed problem report, Wim!  I'm taking the
>>>> liberty to forward to the linux-pci list in case others trip over the
>>>> same thing.
>>>>   
>>>
>>> So, the spec is lying :) and reality doesn't match theory.
> 
> The PCI Express bridge you have is a Broadcom HT 2100 bridge which seems to support
> PCI-Express V1.0 and 1.0a compliant only.
> 
> http://www.hard-net.de/info_wissen/chipsatz/broadcom/HT-2100.pdf
> 
> I can also see this in your lspci output. 
> 
> 00:08.0 PCI bridge: Broadcom HT2100 PCI-Express Bridge (rev a2) (prog-if 00 [Normal decode])
> 	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 19
> 	NUMA node: 0
> 	Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
> 	I/O behind bridge: 0000f000-00000fff [empty]
> 	Memory behind bridge: efe00000-efefffff [size=1M]
> 	Prefetchable memory behind bridge: 00000000fff00000-00000000000fffff [empty]
> 	Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ <SERR- <PERR-
> 	BridgeCtl: Parity+ SERR+ NoISA+ VGA- MAbort- >Reset- FastB2B-
> 		PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
> 	Capabilities: [a0] HyperTransport: MSI Mapping Enable+ Fixed-
> 		Mapping Address Base: 00000000fee00000
> 	Capabilities: [b0] Express (v1) Root Port (Slot-), MSI 00
> 
> I'll post a patch to apply extended tags to systems with PCI express v2 and higher
> bridges only.
> 

Please give this patch a try. I can make the patch pretty and re-post if it works for you. 

You should be seeing messages like this during boot.

[    3.949621] pci 0003:01:00.0: clearing extended tags capability
[    3.959540] pci 0003:01:00.1: clearing extended tags capability
[    3.969454] pci 0003:01:00.2: clearing extended tags capability
[    3.979373] pci 0003:01:00.3: clearing extended tags capability
[    3.989290] pci 0003:01:00.4: clearing extended tags capability



-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.