Received-SPF: pass (google.com: domain of linux-kernel+bounces-29956-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Date: Thu, 18 Jan 2024 11:27:41 +0200 (EET)
To: Jonathan Woithe <jwoithe@just42.net>
cc: Igor Mammedov <imammedo@redhat.com>, linux-pci@vger.kernel.org, 
    Bjorn Helgaas <bhelgaas@google.com>, 
    Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, 
    Rob Herring <robh@kernel.org>, 
    =?ISO-8859-2?Q?Krzysztof_Wilczy=F1ski?= <kw@linux.com>, 
    Lukas Wunner <lukas@wunner.de>, 
    Mika Westerberg <mika.westerberg@linux.intel.com>, 
    Andy Shevchenko <andriy.shevchenko@intel.com>, 
    "Rafael J . Wysocki" <rafael@kernel.org>, 
    LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 0/7] PCI: Solve two bridge window sizing issues
In-Reply-To: <ZajJzcquyvRebAFN@marvin.atrad.com.au>
Message-ID: <c930a6db-f1cd-88e2-03b5-9280b755df08@linux.intel.com>
References: <20231228165707.3447-1-ilpo.jarvinen@linux.intel.com> <20240104131210.71f44d4b@imammedo.users.ipa.redhat.com> <ZZaiLOR4aO84CG2S@marvin.atrad.com.au> <ZZ+gEmxI/TxdbmyQ@marvin.atrad.com.au> <ZajJzcquyvRebAFN@marvin.atrad.com.au>
Precedence: bulk
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="8323328-1115935032-1705570061=:1058"

  This message is in MIME format.  The first part should be readable text,
  while the remaining parts are likely unreadable without MIME-aware tools.

--8323328-1115935032-1705570061=:1058
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: QUOTED-PRINTABLE

On Thu, 18 Jan 2024, Jonathan Woithe wrote:

> On Thu, Jan 11, 2024 at 06:30:22PM +1030, Jonathan Woithe wrote:
> > 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 J=C3=A4rvinen <ilpo.jarvinen@linux.intel.com> wrote:
> > > >=20
> > > > > Hi all,
> > > > >=20
> > > > > Here's a series that contains two fixes to PCI bridge window sizi=
ng
> > > > > 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.
> > > > >=20
> > > > > For the second fix, I chose to expose find_empty_resource_slot() =
from
> > > > > kernel/resource.c because it should increase accuracy of the cann=
ot-fit
> > > > > decision (currently that function is called find_resource()). In =
order
> > > > > to do that sensibly, a few improvements seemed in order to make i=
ts
> > > > > interface and name of the function sane before exposing it. Thus,=
 the
> > > > > few extra patches on resource side.
> > > > >=20
> > > > > Unfortunately I don't have a reason to suspect these would help w=
ith
> > > > > the issues related to the currently ongoing resource regression
> > > > > thread [1].
> > > >=20
> > > > Jonathan,
> > > > can you test this series on affected machine with broken kernel to =
see if
> > > > it's of any help in your case?
> > >=20
> > > Certainly, but it will have to wait until next Thursday (11 Jan 2024)=
=2E  I'm
> > > still on leave this week, and when at work I only have physical acces=
s to
> > > the machine concerned on Thursdays at present.
> > >=20
> > > Which kernel would you prefer I apply the series to?
> >=20
> > 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 boot=
ed
> > but thought it was a different version and therefore none of the module=
s
> > could be found.  As a result, the test is invalid.
> >=20
> > I will try again in a week when I next have physical access to the syst=
em.=20
> > 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 underst=
and
> > it, you want it applied to one of the kernels which failed, making 5.15=
=2Ey
> > (for y < 145) a reasonable choice.
>=20
> I did a "make clean" to reset the source tree and recompiled.  However, i=
t
> errored out:
>=20
>   drivers/pci/setup-bus.c:988:24: error: =E2=80=98RESOURCE_SIZE_MAX=E2=80=
=99 undeclared
>   drivers/pci/setup-bus.c:998:17: error: =E2=80=98pci_bus_for_each_resour=
ce=E2=80=99 undeclared
>=20
> This was with the patch series applied against 5.15.141.  It seems the pa=
tch
> targets a kernel that's too far removed from 5.15.x.
>=20
> Which kernel would you like me to apply the patch series to and test?

Two argument version of pci_bus_for_each_resource() is quite new (so=20
either 6.6 or 6.7). If want to attempt to compile in 5.15.x, you need=20
this:

include/linux/limits.h:#define RESOURCE_SIZE_MAX        ((resource_size_t)~=
0)

And to add one extra argument into pci_bus_for_each_resource(bus, r) in=20
pbus_upstream_assigned_limit():

=09...
=09while ((bus =3D bus->parent)) {
+=09=09unsigned int i;
=09=09if (pci_is_root_bus(bus))
=09=09=09break;

-=09=09pci_bus_for_each_resource(bus, r) {
+=09=09pci_bus_for_each_resource(bus, r, i) {

Note I've written this "patch" by hand inline so patch command cannot=20
apply it but you need to edit those in.


--=20
 i.

--8323328-1115935032-1705570061=:1058--