From: Varsh Satti <varsh@varram.me>
To: Rickey Bartlett <subtexel@gmail.com>
Cc: Nirmal Patel <nirmal.patel@linux.intel.com>,
Jonathan Derrick <jonathan.derrick@linux.dev>,
Lorenzo Pieralisi <lpieralisi@kernel.org>,
Krzysztof Wilczynski <kwilczynski@kernel.org>,
Bjorn Helgaas <helgaas@kernel.org>,
Kai-Heng Feng <kai.heng.feng@canonical.com>,
Keith Busch <kbusch@kernel.org>,
Manivannan Sadhasivam <mani@kernel.org>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI: vmd: Flush initiator posted writes before demuxing interrupts on Meteor Lake
Date: Mon, 12 Oct 2026 14:40:11 -0500 [thread overview]
Message-ID: <20261012194011.48215-1-varsh@varram.me> (raw)
In-Reply-To: <20260825043220.9047-1-subtexel@gmail.com>
On Mon, Aug 24, 2026 at 09:32:20PM -0700, Rickey Bartlett wrote:
> Meteor Lake VMD (8086:7d0b) is affected by erratum MTL016: the VMD can
> signal its MSI before the posted writes carrying a child device's DMA
> data have landed in memory.
Arrow Lake-H is affected too. It uses the same VMD device ID
(8086:7d0b), so the existing match already covers it.
Hardware: ASUS ROG Zephyrus G16 GU605CP (BIOS GU605CP.307), Core Ultra 9
285H, with a WD PC SN5000S (firmware 34230100) as the only device behind
the VMD.
Without the patch, on 7.2.9, I got 13 "timeout, completion polled"
events in about an hour of desktop use. Each one froze the desktop for
up to 30 seconds. Disabling APST and ASPM
(nvme_core.default_ps_max_latency_us=0 pcie_aspm=off) did not help: I
still got 7 in a 10 minute boot.
With the patch backported to 7.2.9, there were no timeouts in 13+ hours
of normal use (~340k reads). Average read latency went from 77 ms to
0.49 ms. Apart from context, the only change the backport needed was
adding struct vmd_dev::features, which 7.2 doesn't have.
Since this fixes 30 second stalls on laptops that are already shipping,
would it be suitable for stable?
Tested-by: Varsh Satti <varsh@varram.me>
next prev parent reply other threads:[~2026-10-12 19:40 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-25 4:32 Rickey Bartlett
2026-09-02 12:28 ` Manivannan Sadhasivam
2026-09-08 23:10 ` Bjorn Helgaas
2026-09-09 1:53 ` Keith Busch
2026-09-09 3:00 ` Rickey Bartlett
2026-10-01 17:08 ` Bjorn Helgaas
2026-10-03 3:40 ` Rickey Bartlett
2026-10-05 23:39 ` Bjorn Helgaas
2026-10-12 19:40 ` Varsh Satti [this message]
2026-10-12 20:19 ` Bjorn Helgaas
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