Re: [coreboot] Investigating the high pitched noise on the x60 tablet

[Peter Stuge]

Charles Devereaux wrote:
  I would like to investigate the whining noise issue.
 
 I have a spare motherboard that I'm setting up for studying this noise
 issue by pinpointing from which component it comes from
..
  by default going into a power saving mode that make
this noise.
The noise is not created by a particular state.

The noise is created by switching between states.

I expect that the noise comes from power supply circuitry.

Use an oscilloscope in clever ways to find the source.

idle=halt skips all C-states.

uhci_hcd requires the CPU to run every ms.

Factory BIOS and coreboot have different noise.

Thermal shutdown is fairly easy to induce when running coreboot,
but not with factory BIOS. X60 has notoriously poor thermal design,
but still there is no thermal shutdown with factory BIOS. Find why.

Understanding the thermal issue might be helpful for the noise issue.

Learn how the factory BIOS manages the CPU power states.

You will not be able to find the documentation you may want for this.


//Peter

Investigating the high pitched noise on the x60 tablet

[The Gluglug]

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sudo powertop

Go to tunables.

Turn everything in "tunables" to "Good" and the noise goes away.

Do this without idle=halt or processor.max_cstate=2 options.
This plus backlight support (see
http://libreboot.org/howto.html#x60_native_notes) you can get battery
life as high as on lenovo bios without any of that noise.

On 09/06/14 22:56, Peter Stuge wrote:
  Charles Devereaux wrote:
  I would like to investigate the whining noise
issue.
 
 I have a spare motherboard that I'm setting up for studying this 
 noise issue by pinpointing from which component it comes from
 ..
  by default going into a power saving mode that
make this noise.
 
 The noise is not created by a particular state.
 
 The noise is created by switching between states.
 
 I expect that the noise comes from power supply circuitry.
 
 Use an oscilloscope in clever ways to find the source.
 
 idle=halt skips all C-states.
 
 uhci_hcd requires the CPU to run every ms.
 
 Factory BIOS and coreboot have different noise.
 
 Thermal shutdown is fairly easy to induce when running coreboot, 
 but not with factory BIOS. X60 has notoriously poor thermal design,
 but still there is no thermal shutdown with factory BIOS. Find
 why.
 
 Understanding the thermal issue might be helpful for the noise 
 issue.
 
 Learn how the factory BIOS manages the CPU power states.
 
 You will not be able to find the documentation you may want for 
 this.
 
 
 //Peter
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Investigating the high pitched noise on the x60 tablet

[Charles Devereaux]

Hello

On Mon, Jun 9, 2014 at 5:56 PM, Peter Stuge <peter(a)stuge.se> wrote:
 
 The noise is created by switching between states.

 I expect that the noise comes from power supply circuitry.

 Use an oscilloscope in clever ways to find the source.
I don't have an oscilloscope, however I created the following script
following glugglug suggestion - it fixes the noise (and also add some
battery life) : http://pastebin.ca/2816554

## reduce sound power consumption (only works while everything is muted)
amixer set Master mute nocap
amixer set CD mute nocap
amixer set Mic mute nocap
echo 'Y' > /sys/module/snd_hda_intel/parameters/power_save_controller
echo '1' > /sys/module/snd_hda_intel/parameters/power_save

## reduce SATA power consumption
for i in /sys/class/scsi_host/host*/link_power_management_policy; do echo
'min_
power' > $i; done

## reduce USB power consumption with autosuspend
for i in /sys/bus/usb/devices/*/power/autosuspend; do echo '1' > $i; done
for i in /sys/bus/usb/devices/*/power/control; do echo 'auto' > $i; done

## other powertop recommanded settings
echo '0' > '/proc/sys/kernel/nmi_watchdog'
# 15 seconds by default, use 60 instead
echo '6000' > '/proc/sys/vm/dirty_writeback_centisecs'
echo '1' > '/sys/module/snd_hda_intel/parameters/power_save'
echo 'min_power' >
'/sys/class/scsi_host/host0/link_power_management_policy'
echo 'auto' > '/sys/bus/usb/devices/5-1/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:05:00.2/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1b.0/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1c.0/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1c.1/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1c.2/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1c.3/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1d.1/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1d.2/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1d.3/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1f.1/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1f.2/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:02.0/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:00.0/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1d.0/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:01:00.0/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:02:00.0/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:05:00.0/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:05:00.1/power/control'
echo 'auto' > '/sys/bus/pci/devices/0000:00:1d.7/power/control'


  Factory BIOS and coreboot have different noise.
All I'm left is with a very small crackling noise, seemingly coming from
the right handside (where the audio jacks are). A new noise, because I
can't remember ever hearing it :-)