Mac OS X Kernel Panics with RTL-SDR/RTL2832U and Analog Discovery, and a Fix

Earlier this week I fired up WaveForms in order to do some spectrum analysis of power supply rails hooked up to a Class D amplifier board using my Analog Discovery. Before I got the Analog Discovery plugged in though, my computer froze, the screen went dark, and then a kernel panic error displayed.

This was new, I’ve never had a problem before, whether or not the device was hooked up before firing up the software. I tried again, this time making sure the Analog Discovery was plugged in before launching Waveforms. Another kernel panic. I tried again, this time plugging it directly into my laptop, rather than the USB3 hub I use for convenience. Another kernel panic. I muttered and cursed and speculated that the cause was the OS X 10.11.6 update I’d recently installed, and ended up using a Windows machine for the task instead.

A few days later, I received a cheap RTL2832 USB DVB receiver I’d purchased in order to (finally) experiment with Software Defined Radio (SDR) using RTL-SDR software. My first explorations were tacked from base camps on my patio and bed. Everything worked without issue. The third time though, I was at my desk, and as soon as I launched CubicSDR my computer froze, went black, and then complained of a kernel panic.

I was peeved. I thought, perhaps that my hub was an issue, so I plugged the RTL2832 in directly. It worked. I tried a different hub. It worked again. I tried something else, it crashed.

Eventually, I figured out that the problem only occurs with a USB3 to Gigabit Ethernet adapter connected (with or without a hub involved). The adapter in question is based on the RTL8153 chip, which is used in USB3 to GigE adapters sold under many different names.

This chip is complaint with standard USB Ethernet protocols, and works with generic drivers provided by Apple in OS X 10.11 (El Capitan), and perhaps earlier versions. I’d installed the Realtek provided driver in order to take advantage of some features of the chip which might improve performance and power consumption, but not to a significant degree.

By removing the Realtek RTL8153 driver using a script provided in the installer package, I was able to revert to using the generic apple USB Ethernet driver. Now, I can use my Analog Discovery with Waveforms, my RTL-SDR with CubicSDR, and my USB3 Ethernet adapter at the same time without Kernel panics.

The Sorry State of Thunderbolt Peripherals

In theory, Thunderbolt is awesome, one tiny port that can be used to connect monitors, GPUs, high speed storage and other peripherals to laptops and desktop computers.  What’s not to like?

Unfortunately, Thunderbolt peripherals are slow to arrive on the scene.  Apple released their first computers with Thunderbolt ports over a year ago. To compliment them, they released the gorgeous and expensive Thunderbolt display.

Don’t get me wrong, the Apple Thunderbolt display is a perfect demonstration of why Thunderbolt is so cool. The display has one cable with two connectors, a magsafe connector to power an Apple laptop, and a Thunderbolt connector.  The display itself is gorgeous, includes speakers and a webcam, and it expands that single Thunderbolt connection into gigabit ethernet, three USB2 ports, a FireWire 800 port, and another Thunderbolt port that you can use to attach another Thunderbolt display, or a mini-DisplayPort adapter. Awesome!


On the other hand, it is $999. That is by no means a bad price for a great 27″ high resolution display, but I’m happy with the 24″ display I already have and in no hurry to replace it. But then there is mess. Ugh! I’d love to reduce that mess down to a power cable and a Thunderbolt cable.

In theory, I should be able to buy a docking station. In practice only Belkin and Matrox have even announced Thunderbolt docking stations, but neither of them are shipping, and when they do, they are expected to run $250 – $500.

Apple had a one-year exclusive on offering Thunderbolt ports on their computers. Now that that has ended, I hope we’ll see more competition, but it may take a while. NewEgg only has ~5 motherboards with Thunderbolt ports right now. A bigger issue though may be that so far, Intel is keeping a tight reign on the chips required to interface with Thunderbolt.

I’d be quite happy with a simple device that connected to a Thunderbolt port and provided USB3 ports and DisplayPort connection. I could hang USB ethernet and audio adapters off of that.