realtek RTL8188CUS slow on Raspberry Pi

I recently had an adventure troubleshooting slow wifi on one of my Raspberry Pi systems. No matter what I did, I could not get more than 57 kilobytes per second transfer speed to it.

akg perception 120 usb mic works on linux

I recently bought an AKG Perception 120 USB microphone to do some voiceover work with.

I couldn't find any reliable source which confirmed whether this works on Linux or not, so hopefully this post will help someone out.

This microphone works great on Linux.

Not only that, it works great full stop. I was using a cheap headset before, and the difference in sound quality is incredible. I'm not any sort of audio expert or audiophile, though I can tell you the constant "hiss" that my old headset produced is eliminated with this new microphone.

I tested using Fedora 18 with kernel 3.9.6-200 which worked fine.
I also tried Ubuntu 13.04 with kernel 3.8.0-19 and that worked too.
However, Ubuntu 12.04.3 with kernel 3.8.0-29 didn't work. It recognised the device but would not pick up sound.

If you wonder about any specific distro, preferably one with a LiveCD, just leave a comment and I'll give it a try if I can.

Here is the output of lsusb on F18 with the device connected:

Bus 001 Device 027: ID 074d:3556 Micronas GmbH Composite USB-Device

Here is the output of dmesg on F18 as the device is connected:

usb 1-1.2: new full-speed USB device number 27 using ehci-pci
usb 1-1.2: New USB device found, idVendor=074d, idProduct=3556
usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-1.2: Product: AKG Perception 120 USB
usb 1-1.2: Manufacturer: AKG Acoustics
ALSA sound/usb/clock.c:243 current rate 0 is different from the runtime rate 48000
ALSA sound/usb/clock.c:243 current rate 0 is different from the runtime rate 48000
usbcore: registered new interface driver snd-usb-audio
ALSA sound/usb/clock.c:243 current rate 48000 is different from the runtime rate 44100
ALSA sound/usb/clock.c:243 current rate 48000 is different from the runtime rate 44100

grub2 usb keyboard not working

I installed the newly released Fedora 17 this week, only to find I could no longer control the GRUB2 screen to get into Windows to play some games. The keyboard and mouse work perfectly in BIOS, and in Linux once USB drivers are loaded, just not at the GRUB2 screen.

Many forum threads exist for this, most pointing towards the "USB Legacy" or similar option in the BIOS. I had this turned on, however turning it off made no difference either.

GRUB2 can load some driver modules, so perhaps it wasn't loading the USB modules. Adding GRUB_PRELOAD_MODULES="usb usb_keyboard ehci ohci uhci" to /etc/default/grub and then rebuilding the config files with grub2-mkconfig -o /boot/grub2/grub.cfg didn't change anything either.

At this point I started coming across articles mentioning UEFI support for GRUB2. UEFI is the "new BIOS" standard coming out on new motherboards. My motherboard is a fairly new model, so it does have EFI firmware.

Turns out the solution is to install a version of GRUB2 with EFI support. This was done with yum install grub2-efi to install the package, then grub2-efi-install /dev/sda to install the EFI-supporting bootloader onto my hard drive. I regenerated a new config with grub2-efi-mkconfig -o /boot/grub2/grub.cfg while I was at it.

Now my USB keyboard works perfectly in GRUB2.