Re: [PATCH RFC v2] bus: mhi: host: pci_generic: Add MBIM-mode config for generic SDX65
From: Jeff Hugo
Date: Fri Nov 13 2026 - 14:07:40 EST
On 11/10/2026 6:06 PM, Haipeng Lin via B4 Relay wrote:
From: Haipeng Lin <jimmie.lin@xxxxxxxxx>I'd like it if we could query the hardware to determine if it is in this mode as maybe one of these systems has a SDX65 dongle attached where this workaround does not apply. However, I am failing to identify such a mechanism so what you have proposed seem to be the best solution so far.
The Surface Pro 11 5G carries an SDX65 that enumerates with Qualcomm's
generic IDs (17cb:0308, subsystem 17cb:0308) but runs the MBIM-mode
firmware it ships with for Windows.
Control is MBIM only (the QMI channel never answers), and data on
channels 100/101 is framed as MBIM NTBs: the modem reports a WDA data
format of raw IP with MBIM aggregation, up to 32 KiB downlink.
The generic qcom-sdx65m entry names channels 100/101 "IP_HW0", which
binds mhi_net. mhi_net expects raw IP, so no data session can work.
The MBIM-mode modules in this driver name them "IP_HW0_MBIM" instead
which binds mhi_wwan_mbim.
Boards with a Qualcomm-ID modem in MBIM mode have so far been told
apart by subsystem ID, like the SC8280XP CRD's SDX55 (17cb:010c).
This modem carries the generic subsystem ID, so select an MBIM
configuration by machine compatible instead.
Unless someone identifies a better idea, this seems reasonable given the situation.
-Jeff