Booting Linux instead of Windows 8 bricks some Samsung laptops

[nsane.forums]

A kernel fix is on the way, but the faulty laptop driver is still in use.

Linux desktop enthusiasts have been booting their operating systems of choice on computers designed for Windows for years now. Windows 8, however, poses some unique challenges because systems with the "Designed for Windows 8" logo must ship with the UEFI secure boot mechanism enabled. That prevents the booting of OSes lacking a signature from a trusted Certificate Authority.

The Linux Foundation came up with a general fix that can address a variety of systems, and there are also solutions designed for specific types of computers. It turns out one of those fixes didn't quite work, and now numerous Samsung laptops are being bricked—that is, rendered unusable and unfixable without a motherboard replacement—when users boot Linux using UEFI.

"According to current understanding, the problem affects at least the following Samsung laptops: NP300E5C, NP530U3C, NP700Z3C, NP700Z5C, NP700Z7C and NP900X4C," The H reported. "The problem came to general attention as the result of a bug report which stated that laptops were bricked after just a single attempt to boot Ubuntu 12.04 or 12.10 in UEFI mode. The problem is also likely to occur with other Linux distributions, since they also include the samsung-laptop driver, which appears to trigger some sort of bug in the UEFI firmware."

Those model numbers refer to Samsung Series 3, Series 5, Series 7, and Series 9 laptops. Linux kernel maintainer Greg Kroah-Hartman explained on Google+ that the culprit is a laptop driver he built—but he built it using code Samsung gave him.

"Hm, who would have thought that just randomly poking memory of a laptop would brick it," Kroah-Hartman wrote. "Long ago Samsung told me that it was just fine to be doing this, and that there would not be any problems (I based the samsung-laptop driver on code that Samsung themselves gave me.) Turns out, it wasn't true, which is sad. Yes, the real solution is to fix the BIOS. If you have this hardware, just blacklist the samsung-laptop driver and all should be fine."

Kroah-Hartman himself was able to run Ubuntu on one of the Samsung laptops without any problems. A bug report shows that it is a problem for some users, though, with one saying, "the boot process panics and throws a machine check exception."

Fortunately, help is on the way. As The H notes, "[Linux creator] Linus Torvalds merged two changes into the main Linux development tree which mean that the samsung-laptop kernel driver will no longer be activated when Linux is booted via UEFI." The change was made yesterday and should result in updates to users "over the next few weeks." Until patches arrive, "users should always use the UEFI firmware's Compatibility Support Module (CSM), which emulates a BIOS mode, when booting on affected laptops."

We sent an inquiry to Samsung to ask if the company can offer any fix, and will provide an update if we get one.

UPDATE: One reader pointed us to a post by Linux developer Matthew Garrett, who notes that "Samsung apparently changed their platform interface when they moved to UEFI, but didn't actually do anything to prevent old drivers from breaking things." The good news is "some of the machines that are affected by this predate Secure Boot, so at least it's not a Secure Boot bug."

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[pweeseonichan]

interesting news. I'll be careful when dealing with uefi now.