Re: [PATCH] PCI/ASPM: Enable ASPM for links under VMD domain

[Kai Heng Feng]

Hi Christoph,

> On Aug 25, 2020, at 2:23 PM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> 
> On Fri, Aug 21, 2020 at 08:32:20PM +0800, Kai-Heng Feng wrote:
>> New Intel laptops with VMD cannot reach deeper power saving state,
>> renders very short battery time.
> 
> So what about just disabling VMD given how bloody pointless it is?
> Hasn't anyone learned from the AHCI remapping debacle?
> 
> I'm really pissed at all this pointless crap intel comes up with just
> to make life hard for absolutely no gain.  Is it so hard to just leave
> a NVMe device as a standard NVMe device instead of f*^&ing everything
> up in the chipset to make OS support a pain and I/O slower than by
> doing nothing?

>From what I can see from the hardwares at my hand, VMD only enables a PCI domain and PCI bridges behind it.

NVMe works as a regular NVMe under those bridges. No magic remapping happens here.

Kai-Heng