[PATCH v2 07/12] arm64: dts: qcom: sc8280xp-x13s: limit pcie4 link speed

From: Johan Hovold <johan+linaro@kernel.org>
To: Bjorn Helgaas <bhelgaas@google.com>,
	Bjorn Andersson <andersson@kernel.org>
Cc: "Konrad Dybcio" <konrad.dybcio@linaro.org>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
	linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Johan Hovold" <johan+linaro@kernel.org>,
	stable@vger.kernel.org
Subject: [PATCH v2 07/12] arm64: dts: qcom: sc8280xp-x13s: limit pcie4 link speed
Date: Fri, 23 Feb 2024 16:21:19 +0100	[thread overview]
Message-ID: <20240223152124.20042-8-johan+linaro@kernel.org> (raw)
In-Reply-To: <20240223152124.20042-1-johan+linaro@kernel.org>

Limit the WiFi PCIe link speed to Gen2 speed (500 MB/s), which is the
speed that the boot firmware has brought up the link at (and that
Windows uses).

This is specifically needed to avoid a large amount of link errors when
restarting the link during boot (but which are currently not reported).

This also appears to fix intermittent failures to download the ath11k
firmware during boot which can be seen when there is a longer delay
between restarting the link and loading the WiFi driver (e.g. when using
full disk encryption).

Fixes: 123b30a75623 ("arm64: dts: qcom: sc8280xp-x13s: enable WiFi controller")
Cc: stable@vger.kernel.org      # 6.2
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts b/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
index 2c17e137563a..a67756ada990 100644
--- a/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
+++ b/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
@@ -768,6 +768,8 @@ &pcie3a_phy {
 };
 
 &pcie4 {
+	max-link-speed = <2>;
+
 	perst-gpios = <&tlmm 141 GPIO_ACTIVE_LOW>;
 	wake-gpios = <&tlmm 139 GPIO_ACTIVE_LOW>;
 
-- 
2.43.0

