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#1 2017-11-15 18:12:48

Stendec
Member
Registered: 2017-11-15
Posts: 3

X1 Carbon Gen 5 sudden restart with graphics card power switching

I have a 5th Gen X1 Carbon with an i5-7200U and Intel Graphics 620. Recently the system began restarting frequently and somewhat randomly whenever I was using X applications (i.e., a WM). Frequently in this case means I was lucky to get 5 minutes of use before a restart, and somewhat randomly means it was not triggered by a specific application (although starting Chromium was a surefire way to cause an immediate restart). Unlike other problems I searched for that had the same solution (see below), there was no kernel panic, no freeze, no hang, no nothing. The computer just restarted as if someone had used the hardware reset (i.e., battery disconnect) button. This made it extremely difficult to diagnose the problem because no logs were generated (the restart was so sudden that even Kdump didn't work).

To cut to the chase, the problem was solved by adding

 i915.enable_rc6=0 

to the kernel options (thanks to oniram for the tip).

Any idea on what's going on here?

Some other, potential useful, information:

  • After a sudden restart the system would boot with zero problems

  • If I didn't run startx then I could use the system with absolutely no problems. This includes very long, resource heavy tasks

  • The problem is the same whether I use xf86-video-fbdev, xf86-video-vesa, or xf86-video-intel drivers and doesn't care if I have an /etc/X11/xorg.conf.d/20_intel.conf or not

  • Apart from disabling UEFI Safe Boot (which is required for Arch) my BIOS settings are default.

  • I ran both Lenovo's builtin hardware diagnostics and memtest86+ with no errors

  • This problem seems to have started after upgrading to kernel 4.13, although it did not go away when I downgraded to 4.12

Thanks for any insights!

(p.s. I'm new to the forums, so I'm not sure if I should mark this as [SOLVED] or not. Sorry for this and any other n00b mistakes)

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#2 2017-11-18 08:53:53

Morok
Member
Registered: 2017-11-17
Posts: 7

Re: X1 Carbon Gen 5 sudden restart with graphics card power switching

What does " i915.enable_rc6=0 " do?

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#3 2017-11-21 16:11:00

Stendec
Member
Registered: 2017-11-15
Posts: 3

Re: X1 Carbon Gen 5 sudden restart with graphics card power switching

According to the wiki it disables power-mode switching in the integrated Intel Graphics processor. With the parameter set to 0 the graphics processor will never enter low power mode and thus this fix will cause the battery to drain quicker. That said, the degradation in battery life is pretty minimal and is certainly better than having a computer that doesn't work.

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