On 05/13/2016 02:33 PM, François Patte wrote:
Le 13/05/2016 18:45, Rick Stevens a écrit :
> On 05/13/2016 02:12 AM, François Patte wrote:
>> Bonjour,
>>
>> The issue now is about wifi connections and usb (!!)
>>
>> If I plug an external usb harddrive, the wifi connection becomes awfull:
>> I tested the rate of transfert from one computer to my updated laptop,
>> using this:
>>
>> dd if=/dev/zero of=test bs=100M count=1; scp test me@laptop:/dev/null;
>>
>> Without any usb hdd plugged, the rate begins at 4.7MB/s and falls down
>> to 2.4MB/s which is acceptable I think.
>>
>> With an usb hdd plugged (I tested with several devices), the rate
>> quickly falls down to 100KB/s sometimes to 20KB/s and sometimes remains
>> completely stalled. Moreover, the wifi connection is very often
>> disconnected (even when there is no tranfert of data at all).
>
> It is not uncommon for a laptop's wifi to be on the USB bus. My Dell
> laptop does precisely this (it is on one of the EHCI controllers).
Yes, it is a laptop Dell (latitude e6540)
Mine is a Inspiron N7110.
>> Why do I think that it an update issue?: 1- because this
behaviour did
>> not happen before the update... 2- I have another laptop (exacttly the
>> same, same brand, same model) which I did not update and this issue does
>> not happen!
>>
>> which of these packages could be responsible for this issue? I can
>> exclude the kernel, because I tested the problem with the previous one
>> (4.4.6) and NetworkManager* because I downgraded them.
>
> There was a kernel 4.4.7-300 between 4.4.6 and 4.4.8. Did you test it?
> Try rebooting into as many of your older kernels as you have and do the
> test.
>
> If the problem only appears on the 4.4.8 kernel, then my guess is that
> kernel-modules for kernel 4.4.8-300 is the issue since that's where the
> USB network and (some) disk drivers come from. I doubt if network
> manager has anything to do with the problem as it simply manages
> connections and has nothing to do with USB bus contention (which is
> what you're probably seeing).
The problem is the same with all kernels: as soon as a hdd is plugged in
an usb port, the rate slows down and even the wifi connection stops. So
it is not a kernel modules problem.
Ok, it could (and I mean "_could_") be a firmware issue with the
underlying USB hardware. I can only suggest two things at this point.
Item 1: See if you can plug the HDD into a port that's on a different
USB device on the machine. You can use the "lsusb -t" utility (as root)
to show you a tree of what's on the USB ports. Mine looks like:
[root@golem4 ~]# lsusb -t
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
|__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M
|__ Port 5: Dev 3, If 0, Class=Wireless, Driver=btusb, 12M
|__ Port 5: Dev 3, If 1, Class=Wireless, Driver=btusb, 12M
|__ Port 6: Dev 4, If 0, Class=Vendor Specific Class, Driver=, 480M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
|__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
|__ Port 4: Dev 4, If 0, Class=Video, Driver=uvcvideo, 480M
|__ Port 4: Dev 4, If 1, Class=Video, Driver=uvcvideo, 480M
The first ehci device has both the bluetooth and wifi on it. The second
ehci device has the webcam on it. Try to plug the HDD into a port
that's not shared with the "wireless" stuff (verify with the lsusb
command). If you can find one, see if that helps.
Item 2: This might be a firmware issue on your laptop. Go to Dell's
site and see if there's an updated firmware version for your machine.
You can find the current version via (again, as root):
dmidecode -s bios-version
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