branch: builtin - notro/rpi-firmware GitHub Wiki

This kernel has the FBTFT drivers built into the kernel proper (kernel.img). It enables the display early in the boot process.

Arguments to fbtft_device have to be specified on the kernel command line (/boot/cmdline.txt).
They also have to be prefixed with the module name.
Example:

fbtft_device.name=rpi-display fbtft_device.rotate=270 fbtft_device.speed=48000000 fbtft_device.fps=50 fbtft_device.debug=0 fbtft_device.verbose=0

The Linux kernel command line has a limit of 1024 bytes. This means that a long custom fbtft_device.init sequence won't fit. The bootloader also adds to the kernel command line.
Show kernel command line length:

$ cat /proc/cmdline | wc -c
525

The kernel also has two special arguments:
* bcm2708.nospi - disable loading of the SPI master driver spi-bcm2708. For parallel interface displays.
* bcm2708.nofb - disable loading of the HDMI/RCA framebuffer, making /dev/fb0 the FBTFT framebuffer.

Other kernel command line parameters

  • fbcon=map:10 - Show console on /dev/fb1
  • fbcon=font:ProFont6x11 - Change boot console font
  • logo.nologo - no boot logo

Firmware: https://github.com/notro/rpi-firmware/tree/builtin

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