Arch Linux

ike

Member

Registered: 2012-10-08

Posts: 6

kexec - garbled screen and hangs

Hi there!

I'm having a bit of a problem here. I wanted to try using kexec on my machine, but I fail to so.
I followed the wiki article about kexec, but when I issue the reboot with

# systemctl kexec

systemd issues a shutdown of the services and I can see the line "Starting the new kernel",
after that, I just get a messed up screen (like really messed up - remember this bsod-screensaver?).
It seems I can't use my keyboard to login and start x.

Some additional info:
(kexec-load.service)

[Unit]
DefaultDependencies=no
Before=shutdown.target umount.target final.target

[Service]
Type=oneshot
ExecStart=/sbin/kexec -l /boot/vmlinuz-linux-ck --initrd=/boot/initramfs-linux-ck.img --reuse-cmdline

[Install]
WantedBy=kexec.target

My kernel commandline:

$ cat /proc/cmdline 
BOOT_IMAGE=/vmlinuz-linux-ck root=UUID=2d4c3996-692d-4c58-af7f-797cf3f7f626 ro ipv6.disable=1 pcie_aspm=force nmi_watchdog=0 i915.i915_enable_rc6=1 init=/usr/lib/systemd/systemd elevator=bfq verbose

Has anyone an idea what could be wrong? I thought it could have something to do with my i915 modules using in my initrd,
but even without those nothing changes.

Cheers

ike

Member

Registered: 2012-10-08

Posts: 6

Re: kexec - garbled screen and hangs

Seems I'm out of luck finding someone who can give me a hint what's going on there.
I posted on the kexec Mailinglist but no answer there as well (perhaps real Messages get buried in the flood of patches there).

I made a "screenshot" with my mobile phone, perhaps someone has an idea here

I'm not sure if this is the right place to ask my questions, but I found very sparse documentation when it comes to solve problems with kexec.

I'm running an arch linux setup on my Macbook Pro 8,1 (Kernel 3.6.7-1-ck) with an i915 vga adapter (Intel HD Graphics 3000) and I try to use kexec with systemd.

Systemd uses a service file to load the new Kernel image before executing kexec:
[SNIP]
[Service]
Type=oneshot
ExecStart=/sbin/kexec -l /boot/vmlinuz-linux-ck \
                --initrd=/boot/initramfs-linux-ck.img\
                --reuse-cmdline
[/SNIP]

I use a system with an encrypted root partition, but I ran into the exact same issue with my old setup (without encrypted root).

But when I issue the kexec call I can read the line
"Starting new kernel" and then my screen is garbled. I read a lot about issues with the vga console, so I tried to reach my system by ssh, but it didn't work.

I uploaded a "screenshot" here: http://imgur.com/UVDT9

Some more info:
[kernel commandline]
BOOT_IMAGE=/vmlinuz-linux-ck root=/dev/mapper/main-root ro cryptdevice=/dev/sda6:main pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 i915.i915_enable_fbc=1 elevator=bfq verbose

[mkinitcpio.conf]
[...]
MODULES="ahci libahci ehci-hcd uhci-hcd ext3 ext4 vfat"
BINARIES="kexec"
FILES="/etc/modprobe.d/modprobe.conf"
HOOKS="base udev keymap fsck autodetect pata scsi sata usbinput encrypt lvm2 uresume filesystems"

Does anyone have a hint how I could "debug" this issue or get kexec to work on my system?

Kind regards