Force backlight on when led matrix is enabled

[qmk_firmware.git] / docs / faq_build.md

diff --git a/docs/faq_build.md b/docs/faq_build.md
index ff409f9c612efbfff988a89d60ea088eeaf7e097..d920d27e2a45ce5a9b4a5b2c6ba5581273258d20 100644 (file)
--- a/docs/faq_build.md
+++ b/docs/faq_build.md
@@ -17,7 +17,7 @@ or just:
 
 Note that running `make` with `sudo` is generally *not* a good idea, and you should use one of the former methods, if possible.
 
-## Linux `udev` Rules
+### Linux `udev` Rules
 On Linux, you'll need proper privileges to access the MCU. You can either use
 `sudo` when flashing firmware, or place these files in `/etc/udev/rules.d/`.
 
@@ -37,6 +37,18 @@ SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ff0", MODE:="066
 SUBSYSTEMS=="usb", ATTRS{idVendor}=="feed", MODE:="0666"
 ```
 
+### Serial device is not detected in bootloader mode on Linux
+Make sure your kernel has appropriate support for your device. If your device uses USB ACM, such as 
+Pro Micro (Atmega32u4), make sure to include `CONFIG_USB_ACM=y`. Other devices may require `USB_SERIAL` and any of its sub options.
+
+## Unknown Device for DFU Bootloader
+
+If you're using Windows to flash your keyboard, and you are running into issues, check the Device Manager.  If you see an "Unknown Device" when the keyboard is in "bootloader mode", then you may have a driver issue. 
+
+Re-running the installation script for MSYS2 may help (eg run `./util/qmk_install.sh` from MSYS2/WSL) or reinstalling the QMK Toolbox may fix the issue. 
+
+If that doesn't work, then you may need to grab the [Zadig Utility](https://zadig.akeo.ie/). Download this, find the device in question, and select the `WinUS(libusb-1.0)` option, and hit "Reinstall driver". Once you've done that, try flashing your board, again. 
+
 ## WINAVR is Obsolete
 It is no longer recommended and may cause some problem.
 See [TMK Issue #99](https://github.com/tmk/tmk_keyboard/issues/99).
@@ -88,3 +100,35 @@ Note that Teensy2.0++ bootloader size is 2048byte. Some Makefiles may have wrong
 #   USBaspLoader     2048
 OPT_DEFS += -DBOOTLOADER_SIZE=2048
 ```
+
+## `avr-gcc: internal compiler error: Abort trap: 6 (program cc1)` on MacOS
+This is an issue with updating on brew, causing symlinks that avr-gcc depend on getting mangled. 
+
+The solution is to remove and reinstall all affected modules. 
+
+```
+brew rm avr-gcc
+brew rm dfu-programmer
+brew rm dfu-util
+brew rm gcc-arm-none-eabi
+brew rm avrdude
+brew install avr-gcc
+brew install dfu-programmer
+brew install dfu-util
+brew install gcc-arm-none-eabi
+brew install avrdude
+```
+
+### avr-gcc 8.1 and LUFA
+
+If you updated your avr-gcc to above 7 you may see errors involving LUFA. For example:
+
+`lib/lufa/LUFA/Drivers/USB/Class/Device/AudioClassDevice.h:380:5: error: 'const' attribute on function returning 'void'`
+
+For now, you need to rollback avr-gcc to 7 in brew.
+
+```
+brew uninstall --force avr-gcc
+brew install avr-gcc@7
+brew link --force avr-gcc@7
+```