Re: [PATCH v32 0/4] MR6315: plugplay: Rework how PnP notifications are sent over RPC to support DBT_DEVTYP_HANDLE events.

[Elizabeth Figura (＠zfigura)]

On Thu Aug 29 23:38:23 2024 +0000, Vibhav Pant wrote:
> @zfigura Testing it is tricky. My plan was to utilize it in the
> bluetooth driver by directly calling `plugplay_send_event` from the
> driver code itself, and I'm not sure what the equivalent of that would
> be in Windows.
> @rbernon I'm okay with using reserved as an offset to pass the device
> path, but we'd still have to pass it for every message for filtering. I
> didn't want to utilize `reserved` mostly out of caution, if it ever
> turned out to be that the field did have some undocumented semantics
> after all.

After doing a bit of research, I believe the Windows interface is IoReportTargetDeviceChange(). See [1], which mentions using that function to report the device notification, and that user mode should register for it with RegisterDeviceNotification().

That function is probably only used for DBT_DEVTYP_HANDLE. I suspect there is no public interface for DBT_DEVTYP_DEVICEINTERFACE. The corresponding kernel-mode identifier for that one is EventCategoryDeviceInterfaceChange, but I suspect that IoReportTargetDeviceChange() only deals with EventCategoryTargetDeviceChange. This would make sense since device interface notifications should only be generated by the kernel anyway.

[I have no idea about the other DBT_DEVTYPE_* values. Are they even ever sent in NT?]

[1] https://learn.microsoft.com/en-us/windows-hardware/drivers/kernel/using-pnp-...