On Wed, Dec 13, 2023 at 03:39:24PM -0800, David E. Box wrote:
On Wed, 2023-12-13 at 14:45 -0600, Bjorn Helgaas wrote: ...
I'd be shocked if Windows treated the BIOS config as a "do not exceed this" situation, so my secret hope is that some of these "broken" devices are really caused by defects in the Linux ASPM support or the driver, and that we can fix them if we find out about them.
But I have no details about any of these alleged broken devices, so it's hard to make progress on them.
I don't have a sense of the scope either. But I could see BIOS not enabling features that would provide no added power savings benefit. We use ASPM to manage package power. There are Intel devices that certainly don't require L1SS for the SoC to achieve the deepest power savings. L1 alone is fine for them. I don't know what the test coverage is for unenabled features. I've sent these questions to our BIOS folks.
Once upon a time there was a push to make it so firmware only had to enumerate boot and console devices and it could skip enumeration and configuration of other devices. But I don't think we've made much progress on that, at least for x86, possibly because Linux depends so much on BIOS resource assignment. IMO that's a Linux deficiency.
Bjorn