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Whole system completely hangs whenever I plug in my NetGear WNA3100M Wireless adaptor (Realtek RTL8192CU chipset) since upgrading to the newest kernel (4.8.0-41). If it's plugged in before start-up, the screen just goes black after the ubuntu loading screen. Ethernet works fine.

When I boot into an older kernel I have installed (4.8.0-22), everything works perfectly.

The syslog doesn't seem to save any messages from the crash, does anyone know how I could get some more debug info out of it? Or even better, just a way to fix it!

I have a picture of the output of text console crashing if it's helpful:

screen photo

Not sure if it's relevant but if I try and boot from recovery mode and start networking I get the error message below repeatedly:

$ grep /etc/resolv.conf
no such file or directory

Output of lsmod | grep rtl:

rtl8xxxu              126976  0
rtl8192cu              65536  0
rtl_usb                20480  1 rtl8192cu
rtl8192c_common        49152  1 rtl8192cu
rtlwifi                77824  3 rtl_usb,rtl8192c_common,rtl8192cu
mac80211              757760  4 rtl_usb,rtlwifi,rtl8192cu,rtl8xxxu
cfg80211              581632  2 mac80211,rtlwifi

Edit: Still not working in the latest kernel 4.8.0-45, but does work on upstream kernel 4.10.0-041000.

Byte Commander
  • 107,489
juliajones
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  • Please edit your question to add the result of the terminal command: lsmod | grep rtl Welcome to Ask Ubuntu. – chili555 Mar 08 '17 at 15:33
  • There have been a couple bugs reported regarding this issue. Specifically this fix released one and this unassigned one – Elder Geek Mar 15 '17 at 12:48
  • Could this be related to this bug? Could you check with 4.8.0-1024.27 (should work) and 4.8.0-1025.28 (should not work)? – mbirth Mar 30 '17 at 23:52
  • @ElderGeek Thanks, but that fix you linked was already included in an older kernel than the one I'm running (4.8.0-41). It's still not working even on the latest update to -45, so I don't think any fix has been released in the meantime! I did install an upstream kernel (4.10.0-041000), which seems to be working apart from having to unplug the wifi adaptor and plug back in for it to be recognised. I'm not familiar with how upstream kernels work... does this mean that this will eventually be an official ubuntu kernel, or should I still file a bug report? – juliajones Apr 04 '17 at 13:07
  • My understanding is that upstream kernels are adopted after passing extensive testing. You may find this useful. https://wiki.ubuntu.com/KernelTeam/KernelUpdates – Elder Geek Apr 04 '17 at 13:19
  • Did this help? – Elder Geek Apr 04 '17 at 13:24

1 Answers1

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It appears that you have two, possibly conflicting drivers loaded. Let's blacklist one and see if there is any improvement. Please open a terminal and do:

sudo -i
echo "blacklist rtl8xxxu"  >>  /etc/modprobe.d/blacklist.conf
exit

Reboot and let us hear your report.

chili555
  • 60,188
  • Thanks for the reply, unfortunately it doesn't seem to have done anything. Not sure if it's relevant but if I try and boot from recovery mode and start networking I get the error message: "grep /etc/resolv.conf no such file or directory" repeatedly. – juliajones Mar 08 '17 at 16:17
  • Thinking about it... aren't the drivers conflicting unlikely to be an issue since it all works fine under the older kernel? – juliajones Mar 08 '17 at 16:31
  • Were both modules present and do they both load in the earlier kernel? Isn't resolv.conf present in both? May we see: dmesg | grep resolv By the way, the only reason I suspect conflicting drivers is because I have seen it and solved it many times previously. – chili555 Mar 08 '17 at 16:51
  • This may be helpful: http://askubuntu.com/questions/608540/i-deleted-my-resolv-conf-how-do-i-get-it-back-or-how-do-i-create-it-again – chili555 Mar 08 '17 at 17:06