Comment 13 for bug 607783

Just to confirm: The dell-wmi messages do not show up when the monitor is plugged in, but only when xrandr is run and the monitor goes black?

If you let it stand for a couple of minutes before hitting Sysrq-REISUB, does the BUG: Soft lockup line show up eventually, without you rebooting?

Otherwise, my knowledge is exhausted on this one, and I hope someone with more kernel knowledge can bring this to the attention of the right upstream.