https://bugs.freedesktop.org/show_bug.cgi?id=101976
--- Comment #12 from Marcelo "Marc" Ranolfi marc.2377@gmail.com --- Kudos for your findings, Pablo Estigarribia.
I made a workaround available in the form of setting DPM to "Low" on system start and calling a script when you need to set it to "High". They can be found at https://gitlab.com/snippets/1709853 and https://gitlab.com/snippets/1709854.
I'm against disabling DPM altogether from the kernel driver code. That'd be far from ideal.