Re: [PATCH v2 0/7] PCI: Solve two bridge window sizing issues

From: Jonathan Woithe
Date: Thu Jan 11 2024 - 03:02:22 EST


On Thu, Jan 04, 2024 at 10:48:53PM +1030, Jonathan Woithe wrote:
> On Thu, Jan 04, 2024 at 01:12:10PM +0100, Igor Mammedov wrote:
> > On Thu, 28 Dec 2023 18:57:00 +0200
> > Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote:
> >
> > > Hi all,
> > >
> > > Here's a series that contains two fixes to PCI bridge window sizing
> > > algorithm. Together, they should enable remove & rescan cycle to work
> > > for a PCI bus that has PCI devices with optional resources and/or
> > > disparity in BAR sizes.
> > >
> > > For the second fix, I chose to expose find_empty_resource_slot() from
> > > kernel/resource.c because it should increase accuracy of the cannot-fit
> > > decision (currently that function is called find_resource()). In order
> > > to do that sensibly, a few improvements seemed in order to make its
> > > interface and name of the function sane before exposing it. Thus, the
> > > few extra patches on resource side.
> > >
> > > Unfortunately I don't have a reason to suspect these would help with
> > > the issues related to the currently ongoing resource regression
> > > thread [1].
> >
> > Jonathan,
> > can you test this series on affected machine with broken kernel to see if
> > it's of any help in your case?
>
> Certainly, but it will have to wait until next Thursday (11 Jan 2024). I'm
> still on leave this week, and when at work I only have physical access to
> the machine concerned on Thursdays at present.
>
> Which kernel would you prefer I apply the series to?

I was very short of time today but I did apply the above series to the
5.15.y branch (since I had this source available), resulting in version
5.15.141+. Unfortunately, in the rush I forgot to do a clean after the
bisect reset, so the resulting kernel was not correctly built. It booted
but thought it was a different version and therefore none of the modules
could be found. As a result, the test is invalid.

I will try again in a week when I next have physical access to the system.
Apologies for the delay. In the meantime, if there's a specific kernel I
should apply the patch series against please let me know. As I understand
it, you want it applied to one of the kernels which failed, making 5.15.y
(for y < 145) a reasonable choice.

Regards
jonathan