linux-kernel - [PATCH 3/5] PCI: qcom: Keep PERST# GPIO state as-is during probe

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20260109-link_retain-v1-3-7e6782230f4b@oss.qualcomm.com>
Date: Fri, 09 Jan 2026 12:51:08 +0530
From: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
To: Vinod Koul <vkoul@...nel.org>, Neil Armstrong <neil.armstrong@...aro.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Jingoo Han <jingoohan1@...il.com>,
        Manivannan Sadhasivam <mani@...nel.org>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kwilczynski@...nel.org>,
        Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>
Cc: linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
        Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
Subject: [PATCH 3/5] PCI: qcom: Keep PERST# GPIO state as-is during probe

The PERST# signal is used to reset PCIe devices. Currently, the driver
requests the GPIO with GPIOD_OUT_HIGH, which forces the line high
during probe. This can unintentionally assert reset early, breaking
link retention or causing unexpected device behavior.

Change the request to use GPIOD_ASIS so the driver preserves the
existing state configured by the bootloader or firmware. This allows
platforms that manage PERST# externally to maintain proper reset
sequencing.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 7b92e7a1c0d9364a9cefe1450818f9cbfc7fd3ac..9342f9c75f1c3017b55614069a7aa821a6fb8da7 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -1711,7 +1711,7 @@ static int qcom_pcie_parse_port(struct qcom_pcie *pcie, struct device_node *node
 	int ret;
 
 	reset = devm_fwnode_gpiod_get(dev, of_fwnode_handle(node),
-				      "reset", GPIOD_OUT_HIGH, "PERST#");
+				      "reset", GPIOD_ASIS, "PERST#");
 	if (IS_ERR(reset))
 		return PTR_ERR(reset);
 
@@ -1772,7 +1772,7 @@ static int qcom_pcie_parse_legacy_binding(struct qcom_pcie *pcie)
 	if (IS_ERR(phy))
 		return PTR_ERR(phy);
 
-	reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
+	reset = devm_gpiod_get_optional(dev, "perst", GPIOD_ASIS);
 	if (IS_ERR(reset))
 		return PTR_ERR(reset);
 

-- 
2.34.1