Dec| www.downtowndougbrown.com
For the next post in my series about upgrading my Chumby 8’s Linux kernel (here are links to parts 1, 2, and 3), I thought I’d look at what was involved in getting the reboot and poweroff commands working properly. I noticed pretty early during the development process that they didn’t work, which was pretty annoying.| Downtown Doug Brown
Way back in part 2 of this series, I first got my Chumby 8 booting into a newer Linux kernel. (Here are links to parts 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 if you want to read the rest of the saga). At that point early on in the project, I had to get the UART driver working. I didn’t spend much time talking about the UART in that post, but it actually gave me a small challenge that I recently had to revisit. I thought it would be fun to tell the full story of the UART struggles I ran into.| Downtown Doug Brown
As my Chumby 8 kernel upgrade project neared the finish line (read parts 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 first if you want), I noticed something subtly annoying. The built-in SD/CF card reader was allocating its own dummy block device (/dev/sda) even if no cards were inserted.| Downtown Doug Brown
I’m going to start this post off with the obligatory list of links to the previous parts in the series if you’re new here and are interested in seeing the full story: 1, 2, 3, 4, 5, 6, 7, 8, and 9. This is the tale of how I upgraded my Chumby 8 to run a modern Linux kernel.| Downtown Doug Brown
If you’re new to this series, I’ve been documenting the process I went through upgrading my old PXA166-based Chumby 8’s 2.6.28 Linux kernel to a modern 6.x version. Here are links to parts 1, 2, 3, 4, 5, 6, 7, and 8. At this point in the project, all of the main hardware peripherals were working great. I noticed something odd when running top though. The CPU usage was always really high, and it wasn’t obvious why.| Downtown Doug Brown
After getting many of the PXA16x peripherals working in modern Linux kernels during my Chumby 8 kernel upgrade saga (here are links to parts 1, 2, 3, 4, 5, 6, and 7), I really felt like I was starting to reach the finish line. The display was working well enough to play low-resolution videos, I had basic 2D acceleration up and running, the touchscreen was operational, and Wi-Fi worked flawlessly. Audio was the only major component left to tackle. The Chumby 8 has built-in speakers, a headphon...| Downtown Doug Brown
After getting the PWM backlight working in my last post (here are links to parts 1, 2, 3, 4, 5, and 6), there was only one piece remaining for having a fully functional display in my Chumby 8: the touchscreen controller. The display output worked perfectly fine but I couldn’t detect presses on it.| Downtown Doug Brown
In the previous post in this series (here are links to parts 1, 2, 3, 4, and 5), I really got the Chumby to start looking like a Chumby. The display was alive! But getting the LCD controller working was really only one puzzle piece when it came to the display. The backlight needed more work so that I could control the brightness, and the touchscreen controller is a completely nonstandard design that is specific to the Chumby.| Downtown Doug Brown