Sunix 2D VGA controller causes kernel panic and crash on boot

[Tommy Giesler]

When using Sunix latest low power VGA or DVI controller (see link below) on Ubuntu 16.04, 17.04 or 17.10 with Kernel 4.11 and later cause the system to crash on boot (the system will not become reachable via network too, so I cannot extract any logs).

By using a second graphics controller I was able to extract the attached kernel message from the system.

The issue also occurs with the latest mainline kernel (tested up to 4.13-rc3).

Sunix changed their graphics chip at some point from Volari Z11 to Silicon Motion SM750. With the older generation, which uses the Z11, everything is working.

Links to the graphics controllers which were previously mentioned:

http://www.sunix.com/en/product_detail.php?cid=1&kid=2&gid=15&pid=1760
http://www.sunix.com/en/product_detail.php?cid=1&kid=2&gid=15&pid=1766

previous generation Sunix 2D VGA controller:
http://www.sunix.com.tw/product/vga0411.html

When using Fedora 26 Server, which also uses Kernel 4.11+, everything is working, too. So I'm not sure, if this is actually an upstream issue.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1707641

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1707641

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Kai-Heng Feng (kaihengfeng)]

Do you mean there's no such issue on 4.10? There's no change on sm750fb between 4.10 and 4.11 though...

[Tommy Giesler (guardion)]

Yes, exactly. There is no issue with Kernel 4.10 (16.04 HWE or 17.04). Current 17.10 Kernel does not boot properly. Unfortunately there are no logs, even on persistent journald. The OS freezes after switching from initramfs to real rootfs.

Any hints what logs I could try to gather to pinpoint this issue?

[Kai-Heng Feng (kaihengfeng)]

Maybe some config changed when v4.10 -> v4.11?
Can you provide the kernel config from the fedora server with linux 4.11?

[Tommy Giesler (guardion)]

I have attached the dmesg log from the booted Fedora and the Kernel config as requested:

[Kai-Heng Feng (kaihengfeng)]

Fedora does not have module sm750fb:
# CONFIG_FB_SM750 is not set

Please file escalate the issue to linux-fb mailing list [1].

In the interim, blacklisting the module should make it work like Fedora.

[1] http://www.spinics.net/lists/linux-fbdev/

[Tommy Giesler (guardion)]

I have sent a message to the mailing list.

You are correct. When blacklisting the module everything is working fine again.

Can you maybe also tell me how do I properly link this bug report to the mailing list?

[Kai-Heng Feng (kaihengfeng)]

Just attach the http link should be sufficient.

[Tommy Giesler (guardion)]

http://marc.info/?l=linux-fbdev&m=150157026614752&w=2