Re: [PATCH] PCI: xgene: Revert "PCI: xgene: Use inbound resources for setup"

From: Marc Zyngier <maz@kernel.org>
To: dann frazier <dann.frazier@canonical.com>
Cc: "Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
	robh@kernel.org, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@android.com,
	"Toan Le" <toan@os.amperecomputing.com>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Stéphane Graber" <stgraber@ubuntu.com>,
	"Thorsten Leemhuis" <regressions@leemhuis.info>
Subject: Re: [PATCH] PCI: xgene: Revert "PCI: xgene: Use inbound resources for setup"
Date: Mon, 21 Mar 2022 09:40:04 +0000	[thread overview]
Message-ID: <87ils7y77v.wl-maz@kernel.org> (raw)
In-Reply-To: <YjN8pT5e6/8cRohQ@xps13.dannf>

On Thu, 17 Mar 2022 18:23:33 +0000,
dann frazier <dann.frazier@canonical.com> wrote:
> 
> On Thu, Mar 17, 2022 at 09:15:43AM +0000, Lorenzo Pieralisi wrote:
> > [removed CC stable]
> > 
> > On Mon, Mar 14, 2022 at 02:44:29PM +0000, Marc Zyngier wrote:
> > > Commit 6dce5aa59e0b ("PCI: xgene: Use inbound resources for setup")
> > > killed PCIe on my XGene-1 box (a Mustang board). The machine itself
> > > is still alive, but half of its storage (over NVMe) is gone, and the
> > > NVMe driver just times out.
> > > 
> > > Note that this machine boots with a device tree provided by the
> > > UEFI firmware (2016 vintage), which could well be non conformant
> > > with the spec, hence the breakage.
> > > 
> > > With the patch reverted, the box boots 5.17-rc8 with flying colors.
> > > 
> > > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > > Cc: Rob Herring <robh@kernel.org>
> > > Cc: Toan Le <toan@os.amperecomputing.com>
> > > Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > > Cc: Krzysztof Wilczyński <kw@linux.com>
> > > Cc: Bjorn Helgaas <bhelgaas@google.com>
> > > Cc: Stéphane Graber <stgraber@ubuntu.com>
> > > Cc: dann frazier <dann.frazier@canonical.com>
> > > Cc: Thorsten Leemhuis <regressions@leemhuis.info>
> > > Cc: stable@vger.kernel.org>
> > > ---
> > >  drivers/pci/controller/pci-xgene.c | 33 ++++++++++++++++++++----------
> > >  1 file changed, 22 insertions(+), 11 deletions(-)
> > 
> > Dann, Rob,
> > 
> > does this fix the regression debated here:
> > 
> > https://lore.kernel.org/all/Yf2wTLjmcRj+AbDv@xps13.dannf
> > 
> > It is unclear in that thread what the conclusion reached was.
> 
> Thanks for checking in Lorenzo! Reverting that patch is required but
> not sufficient to get our m400s working. In addition, we'd also need
> to revert commit c7a75d07827a ("PCI: xgene: Fix IB window setup").
> 
> I believe if we revert both then it should return us to a state where
> Marc's Mustang, Stéphane's Merlins and our m400s all work again.

Right. I'll post a series reverting both patches, which hopefully
Lorenzo and Bjorn can merge shortly.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.