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From: Geraldo Nascimento <geraldogabriel@gmail.com>
To: "Shawn Lin" <shawn.lin@rock-chips.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
	"Manivannan Sadhasivam" <mani@kernel.org>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Geraldo Nascimento" <geraldogabriel@gmail.com>,
	"Dragan Simic" <dsimic@manjaro.org>
Cc: linux-rockchip@lists.infradead.org, linux-pci@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v3 0/2] PCI: rockchip: 5.0 GT/s speed may be dangerous
Date: Wed, 25 Feb 2026 19:26:46 -0300	[thread overview]
Message-ID: <cover.1772057799.git.geraldogabriel@gmail.com> (raw)

Dragan Simic already had warned me of potential issues with 5.0 GT/s
speed operation in Rockchip PCIe. However, in recent interactions
with Shawn Lin from Rockchip it came to my attention there's grave
danger in the unknown errata regarding 5.0 GT/s operational speed
of their PCIe core. Even if the odds are low, to contain any damage,
let's prevent 5.0 GT/s operation as well as add a comment to
Root Complex driver core, documenting this danger of data loss or
worse.

---

Changes in v3:
- Clarify warning message even though Rockchip won't disclose details
- Drop DT changes as they were applied as subset by Heiko
- Link to v2: https://lore.kernel.org/all/cover.1763415705.git.geraldogabriel@gmail.com/

Changes in v2:
- hard limit to 2.5 GT/s, not just warn
- add Reported-by: and Reviewed-by: Dragan Simic
- remove redundant declaration of max-link-speed from helios64 dts
- fix Link: of helios64 patch
- simplify RC mode comment
- Link to v1: https://lore.kernel.org/all/aRhR79u5BPtRRFw3@geday/

---

Geraldo Nascimento (2):
  PCI: rockchip: limit RK3399 to 2.5 GT/s to avoid data loss
  PCI: rockchip-host: comment danger of 5.0 GT/s speed

 drivers/pci/controller/pcie-rockchip-host.c |  4 ++++
 drivers/pci/controller/pcie-rockchip.c      | 10 ++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

-- 
2.52.0


             reply	other threads:[~2026-02-25 22:26 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-25 22:26 Geraldo Nascimento [this message]
2026-02-25 22:27 ` [PATCH v3 1/2] PCI: rockchip: limit RK3399 to 2.5 GT/s to avoid data loss Geraldo Nascimento
2026-02-25 22:27 ` [PATCH v3 2/2] PCI: rockchip-host: comment danger of 5.0 GT/s speed Geraldo Nascimento
2026-02-26  0:12   ` Bjorn Helgaas
2026-02-26  0:18     ` Geraldo Nascimento
2026-02-26  4:52       ` Dragan Simic
2026-02-26  5:06         ` Geraldo Nascimento
2026-02-26  6:52           ` Dragan Simic

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