https://bugzilla.kernel.org/show_bug.cgi?id=201753 --- Comment #14 from David Coe (david.coe@xxxxxxxxxx) --- Good evening, all! Two extra results from the Ryzen 2400G: 1. 5 x 25 msec loop on Ubuntu 21.04, kernel 5.10.11 and Suravee's original patch. Works fine! 2. 10x 20 msec loop on Ubuntu 20.10, kernel 5.8.18 with both Suravee and Alex's patches. Also fine! As expected, AMD-Vi: IOMMU performance counters supported moves to after Adding to iommu group ... This means that, for this CPU, the power-gating needs between 100 - 125 msec to disable. A logging printf would have got me there faster (not overly fond of kernel rebuilds) but the missing information is the maximum settling-time needed across the full Ryzen range. Paul's suggestion of increasing the loop count to 10 gives 200 msec maximum headroom. Surely must be enough? Now, all we need is a work-around for the PCI INT A: not connected diagnostic :-). Many thanks good people. Keep safe. David -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
