On Tue, Jan 2, 2018 at 11:19 AM, Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote: > Hi Carlo, > >>>> Some Realtek bluetooth devices need a "config" blob. The btrtl driver >>>> currently only allows loading this config blob via the request_firmware >>>> mechanism. >>>> >>>> The UART Bluetooth chips use this config blob to specify the baudrate, >>>> whether flow control is used and some other unknown bits. This means >>>> that the config blob is board-specific - thus loading it via >>>> request_firmware means that the rootfs is tied to a specific board. >>>> >>>> The UART Bluetooth chips are implemented through serdev. This means >>>> there is also a devicetree node which describes the Bluetooth chip. >>>> Thus we can also load the blob from the devicetree node to keep the >>>> filesystem independent of any board configuration data. In the future >>>> this could be extended to support ACPI as well (in case that's needed). >>>> >>>> Parse the devicetree node if it exists and obtain the config blob from >>>> there. Otherwise fall back to using the "old" request_firmware >>>> mechanism. >>> >>> where are these config blobs coming from? I think we also need to give people a helping hand on how to add them to DT. I still wonder if the only pieces we are using are the UART config, then maybe skipping the config blob and allowing for clear named values in DT might be better. >> >> What about x86 platforms where we do not have DT (I didn't check but I >> don't think that the UART config in that case is shipped in the ACPI >> tables)? > > if we have this hardware in x86 systems, then I would really like to see ACPI table dumps. Some pieces might need hardcoding based on ACPI ID. Yes, we have, especially on cherry-trail SoCs. In [0] the DSDT of a cherry-trail laptop shipping the rtl8723bs (device OBDA8723). [0] https://gist.github.com/carlocaione/82bff95ababb67dd33f52a86e94ce3ff Cheers, -- Carlo Caione | +44.7384.69.16.04 | Endless -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
