Hello Dieter, On Fri, Feb 02, 2024 at 03:53:36PM +0100, Dieter Mummenschanz wrote: > > > Yes, this part of the problem can be avoided by adding an explicit entry > > that uses "board_ahci_low_power", as I explained in: > > https://lore.kernel.org/linux-ide/ZaATdGDOo5jiBqCR@x1-carbon/T/#u[https://lore.kernel.org/linux-> ide/ZaATdGDOo5jiBqCR@x1-carbon/T/#u] > > > We seem to have a problem with Tiger Lake, but that problem seems to be > > related to Intel VMD. > > > From looking at your logs, you don't seem to have Intel VMD, however > > I'm guessing that some other motherboards that uses Cannon Lake might > > have Intel VMD, so I guess the safest thing is to wait until that issue > > has been resolved before adding a "board_ahci_low_power" entry for > > Cannon Lake. > > This mighht be kind of naive but what about adding an kernel option to force LPM even if the chipset/board is not oficially supported? That is a good suggestion. However, I'm hoping that this series: https://lore.kernel.org/linux-ide/3e50681d-7a68-4c4a-91f6-278a3cfe23f8@xxxxxxx/T/ Will avoid the need for that, as it would kill the "board_ahci_low_power" board type completely. > > > I see now that Damien's revert (patch 2/2 in this series) is not a simple > > $ git revert fd3a6837d8e18cb7be80dcca1283276290336a7a > > it seems to have some other small changes in the same patch as well. > > > Sorry for asking you to test something once more... > > But could you please test with: > > v6.6-rc2 + git revert fd3a6837d8e18cb7be80dcca1283276290336a7a > > No problem. I've explicitly reverted with 6.8-rc2 and have the kernel running for 1 1/2 days now with 3 suspends and on all of them my system transitions to pc8 so I guess we're good but I'll keep on testing to be sure. Hope this helps. After talking with Damien, we are still completely lost. commit fd3a6837d8e1 ("ata: libata-core: Fix ata_pci_shutdown_one()") only modifies the ata_pci_shutdown_one(), which is only called on shutdown. It is not called in the system suspend / system resume path, so it should not be possible for this commit to have an impact. Reading all the emails and bugzilla again, what you are seeing is that: On a fresh boot, and leaving the computer untouched for a few minutes, and looking at e.g. turbostat, some of your CPUs have spent time in the lower-power C-states, e.g. C8/C9/C10. However, if you do a system suspend + system resume, and then leave the computer untouched for a few minutes, and look at e.g. turbotstat, _none_ of your CPUs have spend time in the lower-power C-states. Is this correct? If so, it seems that suspend/resume must have messed up some setting... The commit that added the code to ata_pci_shutdown_one() was added in: 5b6fba546da2 ("ata: libata-core: Detach a port devices on shutdown") This was first added in v6.7-rc1. (So this commit was never included in v6.6.) The code added in 5b6fba546da2 was later removed in: commit fd3a6837d8e1 ("ata: libata-core: Fix ata_pci_shutdown_one()") which was first added in v6.7-rc1. Are you certain that v6.6 works and v6.7 is bad? There are quite few libata patches between v6.6 and v6.7: $ git log --oneline v6.7 --not v6.6 -- drivers/ata Damien has sent many libata patches related to suspend/resume in the last couple of kernel releases, so it is possible that something has regressed. We just have a really hard time seeing how fd3a6837d8e1 could be the bad commit. Kind regards, Niklas
