Created attachment 100101 [details] lspci -vv (from the older kernel) After hibernation with disabled radeon and resuming, vgaswitcheroo thinks that discrete card is powered down, but in fact it is not. It consumes power, and attemts to disable it again hangups the system. Steps to reproduce: 1. Start system, switch to intel (if needed), disable unused card (echo DDIS and OFF to /sys/kernel/debug/vgaswitcheroo/switch) 2. Check power consumption (for example, with powertop) 3. Hibernate the system, resume 4. Check power consumption again, notice increase If attempting to re-disable card (echo ON and OFF) echo hang-ups after ON. If you SIGINT echo, whole system will hangup. On the older 3.8.8 kernel the behaviour is somewhat different: 1. Echo ON and OFF, the power consumption will go down. 2. Hibernate the system again, resume. 3. Notice power consumption increase again. 4. Echo ON. And system hangups just like with newer kernel. A workaround is to enable card before hibernation and disable it after resuming --- it works in both kernels.
Created attachment 100111 [details] dmesg with failure from 3.9-rc8
Created attachment 100121 [details] dmesg after rebooting from failure, 3.9-rc8 Also, after rebooting (with magic-sysrq), the ATI card is not avaliable at all (it doesn't exist in lspci). It can be fixed with poweroff-poweron. Attached dmesg log from this state.
Created attachment 100131 [details] dmesg, 3.8.8