[PATCH v3] usb: core: new quirk to handle devices with zero configurations

[Jie Deng]

Some USB devices incorrectly report bNumConfigurations as 0 in their
device descriptor, which causes the USB core to reject them during
enumeration.
logs:
usb 1-2: device descriptor read/64, error -71
usb 1-2: no configurations
usb 1-2: can't read configurations, error -22

However, these devices actually work correctly when
treated as having a single configuration.

Add a new quirk USB_QUIRK_FORCE_ONE_CONFIG to handle such devices.
When this quirk is set, assume the device has 1 configuration instead
of failing with -EINVAL.

This quirk is applied to the device with VID:PID 5131:2007 which
exhibits this behavior.

Signed-off-by: Jie Deng <dengjie03@xxxxxxxxxx>
---

Changes in v3:
- Modify the string format
Link to v1: https://lore.kernel.org/linux-usb/20260226094737.1306471-1-dengjie03@xxxxxxxxxx/
Link to v2: https://lore.kernel.org/linux-usb/20260227060400.1480039-1-dengjie03@xxxxxxxxxx/
---
 Documentation/admin-guide/kernel-parameters.txt | 3 +++
 drivers/usb/core/config.c                       | 6 +++++-
 drivers/usb/core/quirks.c                       | 5 +++++
 include/linux/usb/quirks.h                      | 3 +++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cb850e5290c2..7d907efe9f49 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -8183,6 +8183,9 @@ Kernel parameters
 				p = USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT
 					(Reduce timeout of the SET_ADDRESS
 					request from 5000 ms to 500 ms);
+				q = USB_QUIRK_FORCE_ONE_CONFIG (Device
+					claims zero configurations,
+					forcing to 1);
 			Example: quirks=0781:5580:bk,0a5c:5834:gij
 
 	usbhid.mousepoll=
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 1cd5fa61dc76..6a1fd967e0a6 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -927,7 +927,11 @@ int usb_get_configuration(struct usb_device *dev)
 		dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
 	}
 
-	if (ncfg < 1) {
+	if (ncfg < 1 && dev->quirks & USB_QUIRK_FORCE_ONE_CONFIG) {
+		dev_info(ddev, "Device claims zero configurations, forcing to 1\n");
+		dev->descriptor.bNumConfigurations = 1;
+		ncfg = 1;
+	} else if (ncfg < 1) {
 		dev_err(ddev, "no configurations\n");
 		return -EINVAL;
 	}
diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index e347236d83e8..7bd408db05f4 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -140,6 +140,8 @@ static int quirks_param_set(const char *value, const struct kernel_param *kp)
 			case 'p':
 				flags |= USB_QUIRK_SHORT_SET_ADDRESS_REQ_TIMEOUT;
 				break;
+			case 'q':
+				flags |= USB_QUIRK_FORCE_ONE_CONFIG;
 			/* Ignore unrecognized flag characters */
 			}
 		}
@@ -589,6 +591,9 @@ static const struct usb_device_id usb_quirk_list[] = {
 	/* VCOM device */
 	{ USB_DEVICE(0x4296, 0x7570), .driver_info = USB_QUIRK_CONFIG_INTF_STRINGS },
 
+	/* Noji-MCS SmartCard Reader */
+	{ USB_DEVICE(0x5131, 0x2007), .driver_info = USB_QUIRK_FORCE_ONE_CONFIG },
+
 	/* INTEL VALUE SSD */
 	{ USB_DEVICE(0x8086, 0xf1a5), .driver_info = USB_QUIRK_RESET_RESUME },
 
diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
index 2f7bd2fdc616..b3cc7beab4a3 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -78,4 +78,7 @@
 /* skip BOS descriptor request */
 #define USB_QUIRK_NO_BOS			BIT(17)
 
+/* Device claims zero configurations, forcing to 1 */
+#define USB_QUIRK_FORCE_ONE_CONFIG		BIT(18)
+
 #endif /* __LINUX_USB_QUIRKS_H */
-- 
2.25.1