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?
Thank you