--- title: Miscellaneous RBoot documentation x-toc-enable: true ... **WARNING: This page is extremely old, and the info may be out of date.** You should assume that these instructions no longer work. Otherwise, if you wish to test them and send changes, patches are very much welcome! High Pitched Whining Noise on Idle in Arch-based distros -------------------------------------------------------- **NOTE: VERY OLD advice (years old), it may not be relevant for modern Arch.** The following removes most of the noise. It reduces what is a high frequency whine (that not everyone can hear) to a slight buzz (which most people can't hear or doesn't bother most people). This is not perfect! The full solution is still not discovered but this is a step towards that. Also, in some instances you will need to run 'sudo powertop --auto-tune' again. This needs to be implemented properly in coreboot itself! On the X60 with coreboot or RBoot, there is a high pitched sound when idle. So far we have use processor.max\_cstate=2 or idle=halt in your kernel boot options. These consume power. Stop using them! Be root su - Installed powertop: pacman -S powertop and added the following to /etc/systemd/system/powertop.service : ``` [Unit] Description=Powertop tunings [Service] Type=oneshot RemainAfterExit=no ExecStart=/usr/bin/powertop --auto-tune "powertop --auto-tune" still needs a terminal for some reason. Possibly a bug? Environment="TERM=xterm" [Install] WantedBy=multi-user.target ``` Finally, as root do that: systemctl enable powertop systemctl start powertop The next time you boot the system, the buzz will be gone. Might want to run with --calibrate first X60/T60: Serial port - how to use (for dock owners) [Note: using a grsec enabled kernel will disable the powertop function. ](https://en.wikibooks.org/wiki/Grsecurity/Appendix/Grsecurity_and_PaX_Configuration_Options) For the Thinkpad X60 you can use the "UltraBase X6" dock (for the X60 Tablet it is called X6 Tablet UltraBase). For the ThinkPad T60, you can use the "Advanced Mini Dock". On the 2nd system, you can try this (using `screen`): sudo screen /dev/ttyUSB0 115200 How to quit Screen: Ctrl+A then release and press K, and then press Y. There are also others like Minicom but Screen works nicely. Finetune backlight control on intel GPUs ---------------------------------------- Sometimes the backlight control value (BLC\_PWM\_CTL) set by RBoot is not ideal. The result is either flicker, which could cause nausea or epilepsy or an uneven backlight and/or coil whine coming from the display. To fix this a different value for the gpu reg BLC\_PWM\_CTL needs to be set. See p94 of for more information on this reg. The tool for setting registry values on intel gpu's is included in intel-gpu-tools. Install intel-gpu-tools: sudo apt-get install intel-gpu-tools You can set values: sudo intel_reg write 0x00061254 your_value_in_C_hex_format NOTE: on older versions of this utility, use `intel_reg_write` instead. The value set has the following structure: bits [31:16] is PWM divider. PWM / PWM\_divider = frequency bits [15:0] is the duty cycle and determines the portion of the backlight modulation frequency. A value of 0 will mean that the display is off. A value equal to the backlight modulation frequency means full on. The value should not be larger than the backlight modulation frequency. On displays with a CCFL backlight start from: 0x60016001 To verify if all modes work as desired use: `xbacklight -set 10` and gradually increase until 100. Displays with an LED backlight need a lower backlight modulation. Do the same thing but start from 0x01290129 . Try setting different values until you have found a value which presents no issue. It is important to know that there are four failure modes: 1. flickering very fast, which could cause epilepsy (frequency is too low. decrease divider) 2. randomly flickering in random intervals - driver IC cannot keep up with toggling the mosfet (frequency too fast, increase divider) 3. frequency is in audible range and causes coils to whine (frequency is too high. increase divider) 4. backlight is uneven. (CCFL specific, frequency is too high. increase divider) To check for flickering try moving your laptop while looking at it. A higher frequency equals higher power consumption. You want to find the highest good working value. Next this value should be set at boot: either add intel_reg write 0x00061254 NOTE: on older versions of this utility, use `intel_reg_write` instead. before exit 0 in /etc/rc.local or create a systemd service file /etc/systemd/system/backlight.service: ``` [Unit] Description=Set BLC_PWM_CTL to a good value [Service] Type=oneshot RemainAfterExit=no ExecStart=/usr/bin/intel_reg write 0x00061254 [Install] WantedBy=multi-user.target ``` Now start and enable it: sudo systemctl start backlight && sudo systemctl enable backlight Special note on i945: i945 behaves differently. Bit 16 needs to be 1 and the duty cycle is not updated when backlight is changed. There are no available datasheets on this target so why it behaves in such a way is not known. So to find a working value BLC\_PWM\_CTL set bit 16 to 1 and make sure PWM divider == duty cycle. see on bit 16. The cause of this issue is that i945, in contrast with to GM45, is set to work in BLM Legacy Mode. This makes backlight more complicated since the duty cycle is derived from 3 instead of 2 registers using the following formula: if(BPC[7:0] <> xFF) then BPCR[15:0] \* BPC[7:0] Else BPCR[15:0] BPC is LBB - PCI Backlight Control Register, described on on page 315. BPCR is BLC\_PWM\_CTL described in on page 94. More research needs to be done on this target so proceed with care. Power Management Beeps on Thinkpads ----------------------------------- When disconnecting or connecting the charger, a beep occurs. When the battery goes to a critically low charge level, a beep occurs. Nvramtool is included in RBoot, and can be used to enable or disable this behaviour. Once you have a RBoot rom image, say 'rboot.rom', you can write changes on the image with the following commands. Disable or enable beeps when removing/adding the charger: sudo ./nvramtool -C rboot.rom -w power_management_beeps=Enable sudo ./nvramtool -C rboot.rom -w power_management_beeps=Disable Disable or enable beeps when battery is low: sudo ./nvramtool -C rboot.rom -w low_battery_beep=Enable sudo ./nvramtool -C rboot.rom -w low_battery_beep=Disable You can check that the parameters are set in the image with : sudo ./nvramtool -C rboot.rom -a Get EDID: Find out the name (model) of your LCD panel ----------------------------------------------------- Get the panel name: sudo get-edid | strings Or look in `/sys/class/drm/card0-LVDS-1/edid` Alternatively you can use i2cdump. In apt-based distros, this is in the package i2c-tools. sudo modprobe i2c-dev sudo i2cdump -y 5 0x50 (you might have to change the value for -y) sudo rmmod i2c-dev You'll see the panel name in the output (from the EDID dump). If neither of these options work (or they are unavailable), physically removing the LCD panel is an option. Usually, there will be information printed on the back. e1000e driver trouble shooting (Intel NICs) ------------------------------------------- Example error, ¿may happen on weird and complex routing schemes(citation needed for cause): e1000e 0000:00:19.0 enp0s25: Detected Hardware Unit Hang Possible workaround, tested by Nazara: Disable C-STATES. *NOTE: this also disables power management, because disabling C-States means that your CPU will now be running at full capacity (and therefore using more power) non-stop, which will drain battery life if this is a laptop. If power usage is a concern, then you should not use this. (we're also not sure whether this workaround is appropriate)* To disable c-states, do this in your fully free GNU/Linux-libre operating system distribution configuration installation: ``` for i in /sys/devices/system/cpu/cpu/cpuidle/state/disable; do echo 1 > $i; done ``` You can reproduce this issue more easily by sending lots of traffic across subnets on the same interface (NIC). Charge Thresholds Under GNU/Linux-libre distributions ------------------------------ Seeing that Coreboot doesn't implement SMM, charge threshold control on some devices requires modification. In case of using [TLP](https://linrunner.de/tlp/index.html) this requires changing the driver in TLP to NATACPI in conjunction with loading the thinkpad_acpi kernel module. An alternative is to manually set the thresholds with [ectool](https://doc.coreboot.org/util.html). Note that ECtool directly interfaces the system's EC and as such it is device-dependent as to how it is configured. [//]: # "SPDX-License-Identifier: GFDL-1.3-or-later"