Re: Ryzen 4000 (Mobile) Softlocks/Micro-stutters

[Jan Beulich <jbeulich@xxxxxxxx>]

On 03.01.2021 07:40, Dylanger Daly wrote:
> Trying to debug Credit2 
> https://wiki.xenproject.org/wiki/Credit2_Scheduler#Dumping_Status_and_Params
> 
> It should be possible to get some debug output on what Credit2 is doing via 
> pressing 'r' on the Serial Debug port
> 
> Does anyone know if it's at all possible to use a USB-TTY adapter? The wiki 
> (https://wiki.xenproject.org/wiki/Xen_Serial_Console) says it's not possible, 
> this makes debugging any modern laptop really hard, I don't think I've ever 
> owned a laptop with a serial port.

If you have a USB2 debug cable and the laptop has a USB2 (EHCI)
debug port directly underneath the host controller (no hubs
inbetween) this should work ("console=dbgp" and some suitable
"dbgp=..."). However, besides USB2 being quite old and typically
laptops coming with newer ports / controllers nowadays, I've
not come across a laptop where the debug port wasn't behind some
hub ...

Jan