Re: possible bug regarding pciehp

[Tormen <tormen@diplomail.ch>]

On 09/02/2015 05:27 PM, Greg KH wrote:
> On Wed, Sep 02, 2015 at 04:35:49PM +0200, Tormen wrote:
>> Hi,
>>
>> I am contacting you, hoping that either you can maybe help
>> or you know someone who can help :)
>>
>> I opened a bug related to the tg3 driver when hot-plugging via pciehp:
>> https://bugzilla.kernel.org/show_bug.cgi?id\x100191
>>
>> I am desperate because :
>> 	(a) there is also a brcmfmac related driver.
>> So both wireless and wired internet have problems:
>> 	https://bugzilla.kernel.org/show_bug.cgi?id\x100201
>> 	(b) there was no input by anybody so far. Maybe because I wrongly
>> categorized the tg3 bug ?
>>
>> The bug is related to Broadcom tg3 driver and the pciehp hotplug framework.
>> In order to sort out where the problem(s) lies, I wanted to kindly ask
>> you if you could have a look at the bug :
>> https://bugzilla.kernel.org/show_bug.cgi?id\x100191
>> ?
>> And/or if you could help me figuring out if pciehp is causing this
>> problem and/or if tg3 is to blame.
> 
> Odds are neither are the issue, this is a thunderbolt problem.  Make
> sure you have enabled thunderbolt properly in your kernel if you want
> hot-add of a device to work.
>
> I think the code has only been tested on older macbooks, changes might
> be needed for newer ones given that Apple's thunderbolt controller is
> "special" (i.e. doesn't follow the specification.)
>
> good luck!
>
> greg k-h
>

Thanks a lot for your feedback !

Is "the code" that you are referring to the thunderbolt kernel module ?

The kernel I am using uses:
CONFIG_THUNDERBOLT=m -- The module will be called thunderbolt.
But when I boot-up with the plugged network device, lsmod does not show
thunderbolt.

So not sure how I can check further if thunderbolt is properly in my kernel?
Or is it possible that I would need to load the thunderbolt module
manually in order to make hotplug work?

When the network driver is loaded it seems to connect as a "PCI Express"
device:
	tg3 0000:0a:00.0 eth0: Tigon3 [partno(BCM957762) rev 57766000] (PCI
Express)

When I unplug the adapter the first thing appearing in dmesg is pciehp:
[  210.992938] usb 1-2: USB disconnect, device number 4
[ 1557.453818] pciehp 0000:06:03.0:pcie24: slot(3-2): Link Down event
[ 1557.453870] pciehp 0000:06:03.0:pcie24: Cannot remove display device
0000:08:00.0
[ 1557.509812] pciehp 0000:06:03.0:pcie24: Card not present on Slot(3-2)
[ 1558.721344] tg3 0000:0a:00.0: tg3_abort_hw timed out, TX_MODE_ENABLE
will not clear MAC_TX_MODEÿffffff
[ 1558.934601] pciehp 0000:09:00.0:pcie24: unloading service driver pciehp
[ 1558.935366] pciehp 0000:09:00.0:pcie24: Timeout on hotplug command
0x1038 (issued 1557532 msec ago)
[ 1558.943460] pci_bus 0000:0a: busn_res: [bus 0a] is released
[ 1558.958426] pci_bus 0000:09: busn_res: [bus 09-0a] is released
[ 1558.958432] acpiphp: Slot [1] unregistered
[ 1558.958451] acpiphp: Slot [2-1] unregistered
[ 1558.958464] acpiphp: Slot [3-1] unregistered
[ 1558.958475] acpiphp: Slot [4-1] unregistered
[ 1558.958486] acpiphp: Slot [5-1] unregistered

But I am not a kernel, pciehp, thunderbolt specialist :(

How can I determine why the pciehp hotplug command 0x1038 timed out ?
Is the "unloading service driver pciehp" the reason why replugging
(hotplugging) the device goes completely unnoticed as far as dmesg goes ?
And if the problem is can (should?) be solved within pciehp ?


For the complete version of the dmesg outputs:
	1. bootup: dmesg___boot-with-plugged-network-adapter.txt
	2. unplug:
dmesg___boot-with-plugged-network-adapter___unplugged-adapter.txt
	3. replug:
dmesg___boot-with-plugged-network-adapter___unplugged-adapter.txt

see:
https://gist.github.com/anonymous/6221168ddcebe37f0ec4


Tormen