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SPEED

The driver supports the following speeds:

  cdiv    speed

     2    125.0 MHz

     4     62.5 MHz

     8     31.2 MHz

    16     15.6 MHz

    32      7.8 MHz

    64      3.9 MHz

   128     1953 kHz

   256      976 kHz

   512      488 kHz

  1024      244 kHz

  2048      122 kHz

  4096       61 kHz

  8192     30.5 kHz

 16384     15.2 kHz

 32768     7629 Hz 

/etc $ grep -rni "fbcp" ./

./rc.local:21:fbcp &

$ cat /boot/config.txt

# For more options and information see

# http://www.raspberrypi.org/documentation/configuration/config-txt.md

# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode

#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible

# and your display can output without overscan

#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console

# goes off screen, and negative if there is too much border

#overscan_left=16

#overscan_right=16

#overscan_top=16

#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus

# overscan.

#framebuffer_width=1280

#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output

#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)

#hdmi_group=1

#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in

# DMT (computer monitor) modes

#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or

# no display

#config_hdmi_boost=4

# uncomment for composite PAL

#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.

#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces

dtparam=i2c_arm=on

#dtparam=i2s=on

dtparam=spi=on

#enable_uart=1

# Uncomment this to enable the lirc-rpi module

#dtoverlay=lirc-rpi

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)

dtparam=audio=on

dtoverlay=waveshare35a:rotate=270

#dtoverlay=ads7846,cs=1,penirq=17,penirq_pull=2,speed=1000000,keep_vref_on=1,swapxy=1,pmax=255,xohms=60,xmin=200,xmax=3900,ymin=200,ymax=3900

#hdmi_force_hotplug=1

#max_usb_current=1

#hdmi_group=2

#hdmi_mode=1

#hdmi_mode=87

#hdmi_cvt 480 320 60 6 0 0 0

#hdmi_drive=2

#display_rotate=2 

$ cat /usr/share/X11/xorg.conf.d/99-fbturbo.conf

# This is a minimal sample config file, which can be copied to

# /etc/X11/xorg.conf in order to make the Xorg server pick up

# and load xf86-video-fbturbo driver installed in the system.

#

# When troubleshooting, check /var/log/Xorg.0.log for the debugging

# output and error messages.

#The driver is made by Waveshare&Spotpear

# Run "man fbturbo" to get additional information about the extra

# configuration options for tuning the driver.

Section "Device"

        Identifier      "Allwinner A10/A13 FBDEV"

        Driver          "fbturbo"

        Option          "fbdev" "/dev/fb0"

        Option          "SwapbuffersWait" "true"

EndSection

Section "Device"

        Identifier      "Waveshare 35a spi"

        Driver          "fbturbo"

        Option          "fbdev" "/dev/fb1"

        Option          "SwapbuffersWait" "true"

EndSection

Section "Monitor"

        Identifier      "primary"

EndSection

Section "Screen"

        Identifier      "primary"

        Device          "Waveshare 35a spi"

        Monitor         "rpi spi"

EndSection 

$ sudo apt-get install gnome-video-arcade mame mame-tools

Reading package lists... Done

Building dependency tree

Reading state information... Done

The following additional packages will be installed:

  liblua5.3-0 libsdl2-2.0-0 libsdl2-ttf-2.0-0 mame-data

Suggested packages:

  devhelp mame-doc mame-extra

The following NEW packages will be installed:

  gnome-video-arcade liblua5.3-0 libsdl2-2.0-0 libsdl2-ttf-2.0-0 mame

  mame-data mame-tools

0 upgraded, 7 newly installed, 0 to remove and 49 not upgraded.

Need to get 45.0 MB of archives. 

$ sudo vi /etc/smsc95xx_mac_addr

~$ pptpsetup

perl: warning: Setting locale failed.

perl: warning: Please check that your locale settings:

        LANGUAGE = (unset),

        LC_ALL = (unset),

        LC_PAPER = "en",

        LC_ADDRESS = "en",

        LC_MONETARY = "en",

        LC_NUMERIC = "en",

        LC_TELEPHONE = "en",

        LC_IDENTIFICATION = "en",

        LC_MEASUREMENT = "en",

        LC_TIME = "en",

        LC_NAME = "en",

        LANG = (unset)

    are supported and installed on your system.

perl: warning: Falling back to the standard locale ("C").

/usr/sbin/pptpsetup: too few arguments.

Try '/usr/sbin/pptpsetup --help' for more information. 

#/etc/environment

LANG="ko_KR.utf8"

LANGUAGE="ko_KR;ko;en_GB;en"

LC_ALL="ko_KR.utf8" 

#!/bin/bash

#Code to stop

/etc/init.d/networking stop

echo 0 > /sys/devices/platform/bcm2708_usb/buspower;

echo “Bus power stopping”

#!/bin/bash

#Code to start

echo 1 > /sys/devices/platform/bcm2708_usb/buspower;

echo “Bus power starting”

sleep 2;

/etc/init.d/networking start 

This tip has been suggested by many people. If your system is headless (no video output) you can turn off the HDMI port with:

sudo /opt/vc/bin/tvservice -o

to turn it back on:

sudo /opt/vc/bin/tvservice -p

This command will save you around 20-30mA. 

$ chcpu

Usage:

 chcpu [options]

Options:

  -h, --help                    print this help

  -e, --enable <cpu-list>       enable cpus

  -d, --disable <cpu-list>      disable cpus

  -c, --configure <cpu-list>    configure cpus

  -g, --deconfigure <cpu-list>  deconfigure cpus

  -p, --dispatch <mode>         set dispatching mode

  -r, --rescan                  trigger rescan of cpus

  -V, --version                 output version information and exit 

$ sudo chcpu -r

chcpu: This system does not support rescanning of CPUs

$ sudo chcpu -e 2

chcpu: CPU 2 is not hot pluggable 

/sys/devices/system/cpu/cpufreq/ondemand $ cat up_threshold

50 

Undervoltage warning

If the power supply to the Raspberry Pi drops below 4.63V (+/-5%), the following icon is displayed. 

$ sudo nano /boot/config.txt

# Disable under-voltage warning

avoid_warnings=1 

Power: Ensure you have a good power supply which can steadily supply at least 2A at 5V. Many power supplies sag voltage and current under maximum load. If you see a lightning bolt icon or rainbow square in the top right corner during regular operation, this is the under-voltage warning and you are not supplying enough power. If you have USB devices plugged into the USB ports, considering getting a good powered USB hub to reduce power draw on the Pi. 

aha so power brownout

Probably, although I haven't done an rpi-update and looked myself, and the commit doesn't say.

It would be the most logical one out of under-voltage and over-temp (yellow or red). 

Finally on the subject of icons, in the past if your Pi was working particularly hard, you might have noticed some yellow and red squares appearing in the top-right corner of the screen, which were indications of overtemperature or undervoltage. These have now been replaced with some new symbols that make it a bit more obvious what’s actually happening; there’s a lightning bolt for undervoltage, and a thermometer for overtemperature. 

pi@raspberrypi:~ $ vcgencmd get_throttled

throttled=0x50000 

pi@raspberrypi:~ $ sudo apt-get install stress stress-ng

pi@raspberrypi:~ $ stress-ng --cpu 4 --io 1 --vm 1 --vm-bytes 128M --timeout 10s --verbose 

Search "avoid_warnings" (1 hit in 1 file)

  D:\Download\linux-rpi-4.9.y\drivers\gpu\drm\vc4\Kconfig (1 hit)

config DRM_VC4

tristate "Broadcom VC4 Graphics"

depends on ARCH_BCM2835 || COMPILE_TEST

depends on DRM

depends on SND && SND_SOC

depends on COMMON_CLK

select DRM_KMS_HELPER

select DRM_KMS_CMA_HELPER

select DRM_GEM_CMA_HELPER

select DRM_PANEL

select SND_PCM

select SND_PCM_ELD

select SND_SOC_GENERIC_DMAENGINE_PCM

select DRM_MIPI_DSI

help

  Choose this option if you have a system that has a Broadcom

  VC4 GPU, such as the Raspberry Pi or other BCM2708/BCM2835.

  This driver requires that "avoid_warnings=2" be present in

  the config.txt for the firmware, to keep it from smashing

  our display setup. 

Red power LED is blinking

A blinking red power LED indicates problems with the power supply. On model A and B, it is hard-wired to the 3.3V power supply rail. If it is blinking, as one user has reported^[1] it means the 5V power supply is dropping out. Use a different power supply.

On model B+ (and presumably also the A+), the circuit has been improved to give a much more reliable warning of poor power quality. The red power LED is wired to an APX803 supervisor^[2] which kicks in when the 5V power supply drops below 4.63V^[3]. If it does, the LED will blink. Check your connections, cable, and power supply.

The Raspberry Pi 2 has a 2.2 amp polyfuse which limits the power which may be supplied via the microUSB socket. This is more than enough to power the Pi and the USB sockets.

Initially the USB sockets can only draw 600 mA. At worst this leaves 1.6 amps for the Pi2 and anything connected to the gpios.

By changing a setting after boot software can configure the USB sockets to draw up to 1.2 amps. At worst this leaves 1 amp for the Pi2 and anything connected to the gpios.

You haven't mentioned connecting anything to the gpios or the USB.

The only meaning to the rainbow square in the top right of the screen is that the 5V line has dropped beneath 4.65V.

If you trust the power supply to be accurate the other cause of low voltage is thin wires in the microUSB cable.