On Thursday, December 19, 2019 at 12:13:57 AM UTC, Claudia wrote:
> This is R4.1 build 20191013
> It works pretty well, definitely better than 4.0, but there are some weird 
> boot issues. If I let it boot with everything as default, it will boot loop 
> before reaching the disk password screen. I found I can get it to boot 
> successfully if I add to the Xen commandline
> noreboot=1 loglvl=all
> and remove from the linux commandline
> rhgb quiet rd.qubes.hide_all_usb
> Still working on narrowing down which of those is/are responsible for 
> fixing the problem (I can't figure out why any of them would).
> Improvements since 4.0:
> Screen power management works - brightness controls, and screen poweroff 
> after inactivity (in 4.0
> it would just blank but not power off)
> Audio works, which it did not work in 4.0 even after many days of 
> troubleshooting
> amdgpu works correctly - doesn't freeze when booting without nomodeset
> Multimedia keys - not sure if they worked in 4.0 or not
> Still working:
> UEFI mode
> wifi
> touchpad
> keyboard
> Still NOT working:
> Suspend/resume
Suspend/resume problem is most likely caused by a recently added security 
feature in Xen, that checks CPUID after resume with the previously (at boot 
time) known CPUID. This is to ensure, that the CPU microcode level - along 
with the resulting Spectere/Meltdown etc. mitigations - still persist after 
system resume and there are no features missing.
For many AMD systems (eg. Trinity/Richland) CPUID changes after suspend 
(some of the high bits), resulting in Xen Panic (see 
xen/arch/x86/acpi/power.c). So, more investigation would be needed to check 
why the CPUID bits are changing after resume and whether it had any 
security implications or not.
For the time being - if you accept the possible security implications - you 
can disable that check eg. by commenting the panic line out after 
"recheck_cpu_features" in the above mentioned power.c file, compile xen for 
dom0 via qubes builder and test it in your system.

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