[PATCH AUTOSEL 6.16-6.1] cdc_ncm: Flag Intel OEM version of Fibocom L850-GL as WWAN

[PATCH AUTOSEL 6.16-6.1] cdc_ncm: Flag Intel OEM version of Fibocom L850-GL as WWAN

[Sasha Levin]

From: Lubomir Rintel <lkundrak@v3.sk>

[ Upstream commit 4a73a36cb704813f588af13d9842d0ba5a185758 ]

This lets NetworkManager/ModemManager know that this is a modem and
needs to be connected first.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://patch.msgid.link/20250814154214.250103-1-lkundrak@v3.sk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

**Backport Status: YES**

This commit should be backported to stable kernel trees for the
following reasons:

## Analysis of the Commit:

1. **Nature of the change**: This is a simple device ID addition that
   adds USB vendor/device ID pair (0x8087:0x095a) for the Intel OEM
   version of Fibocom L850-GL modem to the cdc_ncm driver's device
   table.

2. **Bug fix vs feature**: This is a **hardware enablement fix** rather
   than a new feature. Without this change, the Intel-branded Fibocom
   L850-GL modem won't be properly recognized as a WWAN device, causing
   NetworkManager/ModemManager to fail to handle it correctly. This
   directly impacts users with this hardware.

3. **Code impact**: The change is minimal - just 7 lines adding a new
   entry to the `cdc_devs[]` USB device table:
  ```c
  /* Intel modem (label from OEM reads Fibocom L850-GL) */
  { USB_DEVICE_AND_INTERFACE_INFO(0x8087, 0x095a,
  USB_CLASS_COMM,
  USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
  .driver_info = (unsigned long)&wwan_info,
  },
  ```

4. **Risk assessment**:
   - **Extremely low risk** - The change only adds a new device ID entry
   - No existing functionality is modified
   - Uses the existing `wwan_info` driver configuration (FLAG_WWAN flag)
   - Follows the same pattern as other WWAN devices in the driver
   - Cannot cause regressions for other hardware

5. **User impact**: Users with this specific hardware (Intel OEM version
   with VID:PID 0x8087:0x095a) cannot use their modem properly without
   this fix. The modem won't be recognized as a WWAN device, preventing
   proper network management.

6. **Stable tree criteria compliance**:
   - ✓ Fixes a real bug (hardware not working properly)
   - ✓ Minimal change (7 lines)
   - ✓ No architectural changes
   - ✓ Self-contained to specific hardware
   - ✓ Clear and obvious correctness

7. **Historical context**: The git history shows numerous quirks and
   fixes for the Fibocom L850-GL modem variants, indicating this is
   well-known hardware that has required various fixes over time. This
   particular Intel OEM variant (0x8087:0x095a) was simply missing from
   the device table.

This is a textbook example of a stable-worthy commit: it enables
specific hardware that should already be working, with zero risk to
existing functionality.

 drivers/net/usb/cdc_ncm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index ea0e5e276cd6..5d123df0a866 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -2087,6 +2087,13 @@ static const struct usb_device_id cdc_devs[] = {
 	  .driver_info = (unsigned long)&wwan_info,
 	},
 
+	/* Intel modem (label from OEM reads Fibocom L850-GL) */
+	{ USB_DEVICE_AND_INTERFACE_INFO(0x8087, 0x095a,
+		USB_CLASS_COMM,
+		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
+	  .driver_info = (unsigned long)&wwan_info,
+	},
+
 	/* DisplayLink docking stations */
 	{ .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
 		| USB_DEVICE_ID_MATCH_VENDOR,
-- 
2.50.1