Re: [PATCH] PCI: meson: Remove meson_pcie_link_up() timeout, message, speed check

From: Bjorn Helgaas <helgaas@kernel.org>
To: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>,
	Yue Wang <yue.wang@amlogic.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Kevin Hilman <khilman@baylibre.com>,
	Jerome Brunet <jbrunet@baylibre.com>,
	Linnaea Lavia <linnaea-von-lavia@live.com>,
	FUKAUMI Naoki <naoki@radxa.com>,
	Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>,
	linux-amlogic@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
	stable@vger.kernel.org, Ricardo Pardini <ricardo@pardini.net>
Subject: Re: [PATCH] PCI: meson: Remove meson_pcie_link_up() timeout, message, speed check
Date: Mon, 5 Jan 2026 11:25:43 -0600	[thread overview]
Message-ID: <20260105172543.GA320987@bhelgaas> (raw)
In-Reply-To: <CAFBinCAPpiq=M00ZQXAB4Pu2Myjo8gpXC7DByKkGN6Z_Ahqafg@mail.gmail.com>

On Mon, Jan 05, 2026 at 05:49:00PM +0100, Martin Blumenstingl wrote:
> On Thu, Dec 18, 2025 at 7:06 AM Manivannan Sadhasivam
> <manivannan.sadhasivam@oss.qualcomm.com> wrote:
> >
> >
> > On Mon, 03 Nov 2025 16:19:26 -0600, Bjorn Helgaas wrote:
> > > Previously meson_pcie_link_up() only returned true if the link was in the
> > > L0 state.  This was incorrect because hardware autonomously manages
> > > transitions between L0, L0s, and L1 while both components on the link stay
> > > in D0.  Those states should all be treated as "link is active".
> > >
> > > Returning false when the device was in L0s or L1 broke config accesses
> > > because dw_pcie_other_conf_map_bus() fails if the link is down, which
> > > caused errors like this:
> > >
> > > [...]
> >
> > Applied, thanks!
> >
> > [1/1] PCI: meson: Remove meson_pcie_link_up() timeout, message, speed check
> >       commit: 11647fc772e977c981259a63c4a2b7e2c312ea22
>
> My understanding is that this is queued for -next.
>
> Ricardo (Cc'ed) reported that this patch fixes PCI link up on his
> Odroid-HC4.  Is there a chance to get this patch into -fixes, so it
> can be pulled by Linus for one of the next -rc?

The Fixes tag is for 9c0ef6d34fdb ("PCI: amlogic: Add the Amlogic
Meson PCIe controller driver"), which appeared in v5.0 in 2019, so it
was a latent issue since then.  v5.0 kernels built with
CONFIG_PCIEASPM_POWERSAVE=y or CONFIG_PCIEASPM_POWER_SUPERSAVE=y
should show the same problem.

But I think that latent issue became obvious when the following two
commits essentially made CONFIG_PCIEASPM_POWERSAVE the default for
devicetree platforms:

  f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devicetree platforms")
  df5192d9bb0e ("PCI/ASPM: Enable only L0s and L1 for devicetree platforms")

Those two commits appeared in v6.18, so I think we can make a case
that it fixes a recent problem and is thus material for the current
release.

Moved to for-linus for v6.19 and squashed your unused
WAIT_LINKUP_TIMEOUT fix.  Thanks!

Bjorn

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