Re: [Dorset] How to identify the Cause of a complete Freeze
On Saturday, 30 April 2016 13:44:54 BST Terry Coles wrote: > > > I think I've also seen this on my Dell XPS 13 laptop running Ubuntu > > > 16.04, so the problem may not be KDE related. > > > > Have they both got similar graphics hardware? > > No. This machine has an NVidia GT 720 and the XPS has an Intel Iris > Graphics 540. An update on this which I tracked down this morning. Apparently this issue *is* apparent on both Kubuntu and Ubuntu and, depending on your hardware, can be caused by two distinct problems: Skylake Processors with Iris graphics chipsets: Apparently someone at Intel or Canonical 'forgot' to include support for these processors, so although the machines appear to work, freezing mouse pointers and complete unresponsive machine are being extensively reported. The latest kernel (4.4.48) is supposed to fix this along with issues on AMD graphics cards and a bunch of other stuff. See http://linuxdaddy.com/blog/install-kernel-4-4-on-ubuntu/ Proprietary Driver Support on Kubuntu: Very similar symptoms seem to be occurring on Kubuntu and one of the first things anyone does is to check the graphics drivers. Unfortunately, there's a bug in the Driver Manager which never returns from the 'checking your system' process, see https://bugs.launchpad.net/ubuntu/+source/kubuntu-driver-manager/ +bug/1530523. Consequently, out-of-the-box, Intel machines have no microcode support and if you have a graphics card that would benefit from a proprietary driver it isn't there to install. These drivers can be installed from the repository, but you have to know which ones you want (I got it wrong and killed X functionality until I had installed the right nVidia driver). So far, both machines seem to be pretty stable, but the problem is intermittent, so I may be simply indulging in wishful thinking. I have to say that, yet again, Canonical seem to have released a version too early; pretty unforgivable for an LTS version. -- Terry Coles -- Next meeting: Bournemouth, Tuesday, 2016-06-07 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread: mailto:dorset@mailman.lug.org.uk / CHECK IF YOU'RE REPLYING Reporting bugs well: http://goo.gl/4Xue / TO THE LIST OR THE AUTHOR
Re: [Dorset] How to identify the Cause of a complete Freeze
On Saturday, 30 April 2016 12:32:30 BST Ralph Corderoy wrote:
> Hi Terry,
>
> > Since I upgraded this machine to Kubuntu 16.04, it has been subject to
> > irregular, but fairly frequent freezes. The screen remains frozen on
> > whatever was there at the time, the mouse is stuck and the keyboard is
> > unresponsive.
>
> Have you spotted a pattern; soon after opening a menu, moving a window,
> watching video, that kind of thing?
None that I can see. The problem occurs when I am typing, moving the mouse,
reading text or simply doing nothing.
> Does `coredumpctl' list any core files from around those times? The
> program that's crashed would help with searching, as would the `info'
> from it, see coredumpctl(1).
This is not installed by default, so I installed it earlier today, (before the
last crash). The response is 'No coredumps found'.
> > The thing is, this bug seems to kill the system completely, with only
> > the display retaining its last known content.
>
> Can it be pinged? ping it when it isn't crashed too, so you know it
> normally works.
I hadn't tried that, but it crashed while I was trying to write this reply, so
I pinged it and the interface at least is up.
> > The Magic SysRq sequence doesn't work and my only recourse is to hold
> > down the power button and reboot.
>
> Similarly, does SysRq normally work; it might not be enabled.
Apparently it is not and I need a specially compiled kernel. I've used this
before on other systems. I tried Alt Ctrl Backspace, (which I have enabled),
but that didn't help.
> > I think I've also seen this on my Dell XPS 13 laptop running Ubuntu
> > 16.04, so the problem may not be KDE related.
>
> Have they both got similar graphics hardware?
No. This machine has an NVidia GT 720 and the XPS has an Intel Irus Graphics
540.
> > Is there any way to narrow down the problem so i know what to search
> > for? ('Ubuntu Freezes | crash | stuck' returns nothing useful.)
>
> Mention KDE, desktop, plasma, 16.04. I know it may crash Ubuntu too,
> but you may get better search results by limiting to KDE, assuming it's
> common enough others are suffering. I did find
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1575467 that may be
> related.
How come my search for 'Ubuntu 16.04 Freezes' didn't find that. It seems to
be identical.
--
Terry Coles
--
Next meeting: Bournemouth, Tuesday, 2016-05-03 20:00
Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/
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Re: [Dorset] How to identify the Cause of a complete Freeze
Hi Terry,
> Since I upgraded this machine to Kubuntu 16.04, it has been subject to
> irregular, but fairly frequent freezes. The screen remains frozen on
> whatever was there at the time, the mouse is stuck and the keyboard is
> unresponsive.
Have you spotted a pattern; soon after opening a menu, moving a window,
watching video, that kind of thing?
Does `coredumpctl' list any core files from around those times? The
program that's crashed would help with searching, as would the `info'
from it, see coredumpctl(1).
> The thing is, this bug seems to kill the system completely, with only
> the display retaining its last known content.
Can it be pinged? ping it when it isn't crashed too, so you know it
normally works.
> The Magic SysRq sequence doesn't work and my only recourse is to hold
> down the power button and reboot.
Similarly, does SysRq normally work; it might not be enabled.
> I think I've also seen this on my Dell XPS 13 laptop running Ubuntu
> 16.04, so the problem may not be KDE related.
Have they both got similar graphics hardware?
> Is there any way to narrow down the problem so i know what to search
> for? ('Ubuntu Freezes | crash | stuck' returns nothing useful.)
Mention KDE, desktop, plasma, 16.04. I know it may crash Ubuntu too,
but you may get better search results by limiting to KDE, assuming it's
common enough others are suffering. I did find
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1575467 that may be
related.
Cheers, Ralph.
--
Next meeting: Bournemouth, Tuesday, 2016-05-03 20:00
Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/
New thread: mailto:dorset@mailman.lug.org.uk / CHECK IF YOU'RE REPLYING
Reporting bugs well: http://goo.gl/4Xue / TO THE LIST OR THE AUTHOR
