lkml.org 
[lkml]   [2018]   [Nov]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected
On Tue, Nov 13, 2018 at 10:39:15PM +0000, Alex_Gagniuc@Dellteam.com wrote:
> On 11/12/2018 11:02 PM, Bjorn Helgaas wrote:
> > The whole issue of firmware-first, the mechanism by which firmware
> > gets control, the System Error enables in Root Port Root Control
> > registers, etc., is very murky to me. Jon has a sort of similar issue
> > with VMD where he needs to leave System Errors enabled instead of
> > disabling them as we currently do.
>
> Well, OS gets control via _OSC method, and based on that it should
> touch/not touch the AER bits. The bits that get set/cleared come from
> _HPX method, and there's a more about the FFS described in ACPI spec. It
> seems that if platform, wants to enable VMD, it should pass the correct
> bits via _HPX. I'm curious to know in what new twisted way FFS doesn't
> work as intended.

When VMD is enabled, the platform sees a VMD endpoint. It doesn't see
any of the root ports on that domain, so ACPI can't provide policies for
them nor AER registers for the platform to consider controlling.

\
 
 \ /
  Last update: 2018-11-13 23:56    [W:0.152 / U:47.796 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site