Tobias Diedrich wrote:Possibly a known issue:
After resume pata_amd drops from UDMA/33 to PIO on my system.
Reloading the module puts both attached optical drives (master and
slave) back to UDMA/33.
AFAICS "simplex DMA is claimed by other device, disabling DMA" seems
to be causing it to drop to PIO (but only after a suspend/resume
cycle, not on boot or module load).
Burning a DVD with 6x speed using PIO makes heavy use of burnproof
and makes the whole system quite sluggish. :)
Yes, the fact that it's going into simplex mode is the problem, it wasn't in simplex to start with. It looks like pata_amd does an ata_pci_clear_simplex only for certain chip models, maybe this model needs it as well?