Bluetooth support for Cubox-i

Bluetooth was the last feature of FatdogArm that wasn't working on Cubox-i (it works on the Nexus 7). The last time I looked on it was on April this year. My main problem was I always get the message "can't set hci protocol" near the end of firmware upload, when using the built-in hci driver with brcm_patchram_plus (similar message when using the external hciattach).

There were a lot of people who reported these, and only got the shrugs ... "works for me" type of replies. Most of the "solutions" to this problem concerns about variation of parameters to use on brcm_patchram_plus, as well various links to different versions of .hcd file dumps. However, most of the messages ended there. There were no confirmation whether or not the fix works, and whether there are possibly other causes. And no-one said anything about the kernel.

As it turns out, the kernel *was* the problem. The bluetooth host hardware in cubox-i is connected via MMC SDIO, using the serial interface. To support serial bluetooth devices correctly, the kernel needs BT_HCIUART_* to be enabled. The default defconfig from SolidRun 3.10 kernel did't enable these , and there were no notes whatsoever saying these configs are needed at all . I have been using Solidrun's defconfigs (= manufacturer knows best, etc) - and badly beaten by it, wasting hours on unnecessary debugging

Curiously, SolidRun 3.14 kernel defconfig *does* have these enabled - so they *do* know. Why this isn't documented elsewhere - I have no idea. Go and ask them.

Anyway, as soon as the kernel is rebuilt, bluetooth works. I tested it by getting it paired and connected with a bluetooth speaker and bluetooth keyboard. Both works nicely.

I have integrated these findings into a package called imx6-bluetooth, and have uploaded it to the repo. However, it won't work unless you use a kernel with those configs enabled.

I'm going to upload a new kernel for cubox-i later. If you're interested to use it *now*, then leave me a message.

With this, the FatdogArm platform support for cubox-i is considered complete.

Posted on 17 Sep 2015, 00:02 - Categories: FatdogArm Linux Arm Fatdog64
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