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From: Selvarasu Ganesan <selvarasu.g@samsung.com>
To: Thinh.Nguyen@synopsys.com, gregkh@linuxfoundation.org,
	paulz@synopsys.com, balbi@ti.com, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: jh0801.jung@samsung.com, akash.m5@samsung.com,
	h10.kim@samsung.com, alim.akhtar@samsung.com,
	thiagu.r@samsung.com, muhammed.ali@samsung.com,
	Selvarasu Ganesan <selvarasu.g@samsung.com>,
	stable@vger.kernel.org,
	Pritam Manohar Sutar <pritam.sutar@samsung.com>
Subject: [PATCH v2] usb: dwc3: Move GUID programming after PHY initialization
Date: Fri, 17 Apr 2026 12:03:11 +0530	[thread overview]
Message-ID: <20260417063314.2359-1-selvarasu.g@samsung.com> (raw)
In-Reply-To: CGME20260417063502epcas5p4f8f7fefb697e6d130ef7e9a78581ed84@epcas5p4.samsung.com

The Linux Version Code is currently written to the GUID register before
PHY initialization. Certain PHY implementations (such as Synopsys eUSB
PHY performing link_sw_reset) clear the GUID register to its default
value during initialization, causing the kernel version information to
be lost.

Move the GUID register programming to occur after PHY initialization
completes to ensure the Linux version information persists.

Fixes: fa0ea13e9f1c ("usb: dwc3: core: write LINUX_VERSION_CODE to our GUID register")
Cc: stable@vger.kernel.org
Reported-by: Pritam Manohar Sutar <pritam.sutar@samsung.com>
Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
---
 drivers/usb/dwc3/core.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 161a4d58b2cec..0d3c7e7b2262f 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1341,12 +1341,6 @@ int dwc3_core_init(struct dwc3 *dwc)
 
 	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
 
-	/*
-	 * Write Linux Version Code to our GUID register so it's easy to figure
-	 * out which kernel version a bug was found.
-	 */
-	dwc3_writel(dwc, DWC3_GUID, LINUX_VERSION_CODE);
-
 	ret = dwc3_phy_setup(dwc);
 	if (ret)
 		return ret;
@@ -1378,6 +1372,12 @@ int dwc3_core_init(struct dwc3 *dwc)
 	if (ret)
 		goto err_exit_phy;
 
+	/*
+	 * Write Linux Version Code to our GUID register so it's easy to figure
+	 * out which kernel version a bug was found.
+	 */
+	dwc3_writel(dwc, DWC3_GUID, LINUX_VERSION_CODE);
+
 	dwc3_core_setup_global_control(dwc);
 	dwc3_core_num_eps(dwc);
 
-- 
2.34.1


       reply	other threads:[~2026-04-17  6:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20260417063502epcas5p4f8f7fefb697e6d130ef7e9a78581ed84@epcas5p4.samsung.com>
2026-04-17  6:33 ` Selvarasu Ganesan [this message]
2026-04-17  7:02   ` [PATCH v2] usb: dwc3: Move GUID programming after PHY initialization Selvarasu Ganesan
2026-04-17 23:13   ` Thinh Nguyen

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