On 05/16/2016 12:37 AM, François Patte wrote:
Le 13/05/2016 23:53, Rick Stevens a écrit :
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)
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.
I get exactly the same answer as yours for lsusb -t and the problem
remains regardless the usb port where I plug the hdd.
But now the problem become worse: with or without a hdd plugged, the
wifi connection is unusable because the bitrate falls down in a few
seconds (from 4MB/s to 20KB/s and, after that, remains stalled for a
long time)...
Could it be a hardware problem and, if yes, is there a way to test the
integrity of the wifi card?
So it now appears that the issue isn't USB bus contention with the HDD,
it appears to be purely wifi? Double check that you don't have something
else competing for either wifi or USB operations (e.g. a dnf cache
refresh) when you see the issue occur.
Debugging wifi is always problematic since it's difficult to isolate if
the issue is with the NIC on the laptop or the access point at the
other end. You could try taking your machine to somewhere like an
internet cafe or somewhere else you have wifi access to see if the
problem persists there (make sure you have your firewall up and you
don't have any personal info exposed). If it persists, then yeah, your
wifi may be going bad. If it doesn't, that points at issues with your
access point. To be honest, I've had access points go bad far more often
than the NIC in the laptop.
----------------------------------------------------------------------
- Rick Stevens, Systems Engineer, AllDigital ricks@xxxxxxxxxxxxxx -
- AIM/Skype: therps2 ICQ: 226437340 Yahoo: origrps2 -
- -
- To err is human. To forgive, a large sum of money is needed. -
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