Klystron, Kernel Update a Success

The laptop which I name ‘Klystron’, received a Kernel Update on July 7. This brought its kernel version to 4.4.0-30-generic as far as I can tell.

Prior to this update, one of the problems the laptop was still experiencing, was due to its Realtek WiFi chip-set, and the kernel module ‘RTL8723BE’. It had a malfunction in how it was connecting to my WiFi, which should have set in twice again, since July 7, according to earlier observations I had made. This bug had become quite predictable.

But since the latest kernel update, this malfunction has not been taking place anymore.

So I would say, that this kernel update was a huge, welcome success.

A separate question I have not yet answered, was whether its Suspend Behavior has also been corrected. This will be slightly more complicated for me to test, because as the above posting suggests, I had adapted a script, which seems to correct it. If the problem had been resolved in the kernel update, my script would simply not do anything. And the end result would remain, that the problem is not apparent.

In order to see whether the kernel update actually resolved that issue, I would first need to disable my script, and then try a few Suspend Cycles, since this problem was also not taking place with 100% consistency.

I have not yet committed myself to doing that.

Dirk

 

Klystron Kernel Update

My Linux laptop named ‘Klystron‘ is still fully subscribed to the “Kanotix” repositories. As the reader may recall, Kanotix is a slightly customized version of Debian Linux, that is KDE-based, and that is maintained by a group of developer-experts who I trust implicitly.

Being subscribed to their specific repositories and configuration details has as one advantage, that periodic kernel updates are fed to me, via package manager.

As I came home from camping yesterday, on July 7, I also rebooted this laptop, and saw that indeed, a kernel update was being offered, which I immediately installed. So that laptop now has kernel version ‘4.4.0-30-generic‘, or so my /boot directory would seem to say.

One problem that I was experiencing with that laptop since before camping, was some subtle WiFi issue which I could no longer pinpoint. I had written, that its ability to use the hardware encryption offered by the (kernel module ‘RTL8723BE’) chip-set seemed to work fine. But there were some other problems with the WiFi.

I would like to be able to report, when and if that issue has been resolved completely. But since Klystron has only been running on kernel version 4.4.0-30-generic for one day, it is still far too soon to call out a victory. I will continue to observe the behavior of that laptop for the next little while, and give further comment on it later. So far its behavior looks good.

Dirk

 

My WiFi connection has been stable, for 1 day and 13 hours.

On my newly set-up laptop ‘Klystron’ I had reported This Problem with the stability of the WiFi chip-set. Well since that posting, that laptop has been able to stay idle – and connected – for 1 day and 13 hours, without disconnecting. And, I have downloaded lengthy hundreds of megabytes – and sometimes gigabytes – of software packages, without any further interruptions.

Thus, even if there is still a problem with my Pidgin client sometimes disconnecting with a “Ping Timeout”, this problem should be external to the behavior of the WiFi kernel module now, and may even have something to do with policies from the IRC chat room, such as ‘No More Than 1 Nick Per User Logged On At Once’ ?

Dirk

 

Stabilizing my Realtek rtl8723be WiFi card under Linux.

The laptop of mine onto which I newly installed Kanotix / Spitfire, and that is named ‘Klystron’, happens to have a Realtek rtl8723be WiFi chip-set, which is known to have stability issues under Linux. I found that recently my own experience also ran into these issues.

If you feel that you are also having these issues, it is important that you first check, whether in fact you have the WiFi card in question. This can be done via an ‘lspci‘ command, or with


lsmod | grep rtl8723

I felt that I needed to apply a two-prong solution to my own problem.

The first thing which I did, was to create a file named


/etc/modprobe.d/rtl8723be.conf

The only content of which was the line


options rtl8723be fwlps=0 swlps=0

This solution may solve the problem, of the WiFi dropping the connection, after periods of idle time.

There is something to watch out for. There are some sources on the Web, which state that we should try  the configuration line


options rtl8723be fwlps=N swlps=N

The problem with this method is, that for certain uses in programming, in particular in the language C, which is used for kernel modules, a numeric value may be expected in place of a Boolean value, and if in this case the module sees an ‘N’, this value will not be equal to zero, because the ASCII code for ‘N’ is not zero, and any other value than zero is taken to be True! So to make sure that the kernel module registers False, we need to put a ‘0’.

But I found that a second issue was affecting me, which was the fact that this WiFi setup has IPv6 enabled, but that my router does not tolerate IPv6. This may have been causing my laptop to get dropped from the WiFi, even as I was downloading software. In my dhcp configuration, I have added the DNS Server 8.8.8.8, which is the free Google DNS server, in addition to the auto-detected server. But 8.8.8.8 will offer the system an IPv6 resolution of a domain name along with an IPv4 resolution, and in the case of WiFi, apparently Linux will use the IPv6, without detecting that this ability was not assigned by the Access Point.

And so I felt that I also needed to disable IPv6 system-wide on this laptop. The way to do that was to add the following lines to the file ‘/etc/sysctl.conf‘:


net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

And then ‘sysctl -p‘. After that, I also did


update-initramfs -u

This is a very sticky issue, in which different users have reported, that some of these solutions either do or do not work for them. One reason may be, that users are in fact reporting different issues without knowing it. I cannot be sure that this solution will remain 100% effective for myself, let alone for the reader. I just wanted to share my own experience with this. So far, my WiFi chipset is stable again.

(Edit 04/12/2016 : ) Just to prove to you, how uncertain the state of that WiFi chip-set is, even though I did change the parameters fed into this kernel module, it still happens that when I leave that laptop idling overnight, its WiFi goes into suspend mode. This happens in a way which the applications usually do not see, so that those applications still think they’re connected. However, my ‘Pidgin’ IRC Client gets disconnected.

And then, when I resume my session, ‘Pidgin’, which uses a ping timeout, did realize it was disconnected, and just reconnects seamlessly. And this latter part seems to happen, directly after I unlock my screen-saver, which seems to suggest that this is not being introduced by the Kernel Module, but rather by KDE, etc. I suppose it might introduce some level of confusion into the software, if the Kernel Module was to provide the same function again.

So who knows, which of my problems – if any – I may really have fixed?

Just checking my package manager, I see that ‘Pidgin’ has an available ‘Away-On-Lock’ plugin, which was not installed. Just this evening I installed and activated that, just to see whether I can override a behavior, which might have been set erroneously to ‘Offline-On-Lock’, while the plugin was not installed… By tomorrow, I should know.

Dirk