On Tue, May 02, 2017 at 12:49:29PM +0200, Lukas Wunner wrote: > On Mon, May 01, 2017 at 10:41:20PM -0400, Sinan Kaya wrote: > > On 5/1/2017 9:54 PM, Lukas Wunner wrote: > > > (b) ASPM L1 enabled on boot, but disabled after powering off and back on > > > => I believe Sinan is working on this (+cc). > > > > The decision was made not to touch ASPM registers following hotplug insertion > > unless pcie_aspm.policy=powersave is specified. > > > > The discussion is here: https://lkml.org/lkml/2017/4/17/255 > > > > This was done to maintain existing behavior and not break things. > > Thanks for the reference, I hadn't followed the discussion in April > very closely, but I think the outcome of the discussion is unfortunate. > > As can be seen in Ashok's tests, merely turning slot power off and back > on is sufficient to end up with a setting that draws more power. That > may be equally surprising for users as the issues would be that we seek > to avoid with a "safety-first" ASPM policy. In any case it seems > undesirable. > > I hope this is not the end if it and would like to encourage you to > keep working on this. Perhaps it is too simple to just define a > default policy, and what is really needed is a policy that adjusts > itself dynamically to specific devices or workloads, or that can be > influenced by device drivers. It's not the end of the discussion. If you have an alternate proposal, we'd love to hear it, especially if you implement it.
