Linux on Acer 1410, 1810TZ and 1810T

[PatrickVogeli]

UPDATED FOR UBUNTU 10.04 LUCID LYNX

Here it comes, updated guide for Lucid.

Packard Bell / Gateway clones:
This guide has also been tested on a Packard Bell Dot M/U with bios v3303, and it should also work on the Gateway clone. If you have a 1410/1810 and something doesn't work, please report back.

What's working after a standard Ubuntu 10.04 install:

• Graphics
• Audio out, speaker mutes when pluging in headphones. Good volume.
• Networking, both wireless (intel wifi 1000) and wired (the atheros gigabit)
• FN +:
  • F4, suspends fine
  • F6, monitor goes black
  • F7, touchpad on / off
  • F8, mute
  • F9, Bloq Num
  • RePag: Home
  • AvPag: End
  • Up: increase volume
  • Down: decrease volume
  • Righ: increase brightness: skips steps.
  • Left: decrease brightness: skips steps.
  • J,K,L, etc: numeric keyboard ok.

What's not working:

• Audio in: the integrated mic doesn't work.
• FN + F5: not recognised, doesn't toogle displays

Automated Install (recommended):

I've done a script that should do it all automatically. In detail:

What the script does:

• Configure gnome-power-manager backlight dim and hard disk power saving
• Download, patch, install and setup acerhdf
• Install the power saving script
• Install the debugging script
• If laptop-mode-tools is installed, suggest uninstalling and, if you want, uninstall
• Fix the brightness hotkeys issue (jumps 2 levels on every key press)
• Disable ethernet Wake on Lan (doesn't enable when on AC)
• Disable uneeded services: cron, anacron and atd (they don't enable when on AC)

What the script doesn't:

• Add the noatime parameter to the ext2/3/4 partitions in fstab. You'll have to do it manually.

How it works:

• In a terminal, run ./InstallAcer_11.6_PowerSaving.sh --help to get a full list of options.
• If you want to install everything: ./InstallAcer_11.6_PowerSaving.sh --install

Disclaimer:

• This script comes with no warranty. Use it at your own risk. I won't be responsible for any damage this could do to your system or data.

Manual Install:

Power saving tips:

The Script:

By default, an ubuntu install won't take too much care of saving power, which is very important in an ultra mobile laptop. You can easily setup the system to enter some power saving modes, specifically the sata controller and the sound chip.

I've setup a script which will take care of making the devices entering the power saving mode when the laptop is on battery.

#!/bin/bash

      ## Disable unnecessary services
      service atd stop
      service cron stop
      service anacron stop
      ## Acer 11.6 brightness hotkey fix
      echo N > /sys/module/video/parameters/brightness_switch_enabled
      ## Disable wake on lan
      ethtool -s eth0 wol d

  if on_ac_power; then
  #### Go fast on AC power.  Similar to default Ubuntu settings
  
      # Remount ext3/4 filesystems to default value: every 5 seconds
      mount -o remount,commit=5, /
      mount -o remount,commit=5, /home

      ## Set swap usage back to default
      echo 60 > /proc/sys/vm/swappiness

      ## Disable Sata Power Saving
      for foo in /sys/class/scsi_host/host*/link_power_management_policy;
        do echo max_performance > $foo;
      done

      ## Disable Intel Wlan Power Saving
      iwconfig wlan0 power off

      ## Disable HD Audio Power Saving
      echo 0 > /sys/module/snd_hda_intel/parameters/power_save
      echo N > /sys/module/snd_hda_intel/parameters/power_save_controller

      ## Set kernel dirty page value back to default
      echo 20 > /proc/sys/vm/dirty_ratio
      echo 10 > /proc/sys/vm/dirty_background_ratio
      echo 500 > /proc/sys/vm/dirty_expire_centisecs
      echo 500 > /proc/sys/vm/dirty_writeback_centisecs 
      
  else 
  #### Save power

      ## Change the ext3/4 commit times to 10 minutes.  Reduces disk activity
      mount -o remount,commit=600 /
      mount -o remount,commit=600 /home

      ## Reduce swap usage as much as possible
      echo 1 > /proc/sys/vm/swappiness

      ## Enable Sata Power Saving
      for foo in /sys/class/scsi_host/host*/link_power_management_policy;
        do echo min_power > $foo;
      done

      ## Enable Intel Wlan Power Saving
      iwconfig wlan0 power on

      ## Enable HD Audio Power Saving
      echo 10 > /sys/module/snd_hda_intel/parameters/power_save
      echo Y  > /sys/module/snd_hda_intel/parameters/power_save_controller

      ## Reduce disk activity by waiting up to 10 minutes before doing writes
      echo 90 > /proc/sys/vm/dirty_ratio
      echo 25 > /proc/sys/vm/dirty_background_ratio
      echo 60000 > /proc/sys/vm/dirty_expire_centisecs
      echo 60000 > /proc/sys/vm/dirty_writeback_centisecs
      
  fi

To install this power saving script, do the following:

gksudo gedit /etc/pm/power.d/15_saving
# Paste the script above into the file, save and close
sudo chmod +x /etc/pm/power.d/15_saving
sudo ln -s /etc/pm/power.d/15_saving /etc/pm/sleep.d/
sudo chown root /etc/pm/power.d/15_saving
sudo chgrp root /etc/pm/power.d/15_saving

gnome-power-manager:

Go the g-p-m preferences, under System -> Preferences -> Power management, and do the following:

• Hard drive power saving: in the battery tab tick on "Reduce hard drive revolutions when possible"
• Battery tab: tick on reduce brightness and dim display.
• AC and Battery tab: configure what to do when closing the lid and what to do on very low battery remaining.
• General tab: configure what to do when pressing the power button and sleep button (Fn+f4).
• General tab: configure when to show the battery icon.

The “noatime” parameter:

In linux, and in ubuntu it's on by default, the filesystem has 3 types of date information: when the file was created, when the file was modified and when the file was last accessed. This last access information means that everytime a file is accessed (everytime you read a file), it does a file system write, to update the information. In My Honest Opinion, this is not necessary, and I would disable the last access information. How? Editing fstab and adding the noatime paramenter to all ext2/3/4 mounted partitions. You can edit fstab by doing gksudo gedit /etc/fstab and, there, add the parameter noatime to all the ext2/3/4 lines. Example on how the relevant fstab lines look in my machine:

UUID=VERY-LONG-NUMBER  /       ext4  errors=remount-ro,noatime   0       1
UUID=VERY-LONG-NUMBER  /home   ext4  defaults,noatime            0       2

There may be people who may find the atime parameter interesting, I don't. Hard drives are already the biggest bottlenecks in computers, and doing extra writes won't improves things, so I prefer to avoid them.

Issues:

Fan:

Issue: the fan is controlled by the BIOS, and is running too loud and too often.
Solution: the solution is installing an update acerhdf module. Download the laster version from here. There's a great chance that it will work without any additional work, skip the next lines and go ahead on to how to install acerhdf.
If after installing acerhdf it doesn't work, you'll have to patch it adding your BIOS version. Open the acerhdf.c file and add the following code above this line: '/* pewpew-terminator */':

/* Acer 1410 */
{"Acer", "Aspire 1410", "v0.3108", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1410", "v0.3113", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1410", "v0.3119", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1410", "v0.3117", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1410", "v1.3204", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
/* Acer 1810T(Z) */
{"Acer", "Aspire 1810T", "v0.3108", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810TZ", "v0.3108", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810T", "v0.3113", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810TZ", "v0.3113", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810T", "v0.3117", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810TZ", "v0.3117", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
/* Packard Bell clone */
{"Packard Bell","DOTMU","v0.3108", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Packard Bell","DOTMU","v0.3113", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Packard Bell","DOTMU","v0.3115", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Packard Bell","DOTMU","v0.3117", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Packard Bell","DOTMU","v0.3119", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Packard Bell","DOTMU","v1.3204", 0x55, 0x58, {0x9e, 0x9e, 0x00} },

Save and close. Let's go on into compiling it:

cd /to/the/acerhdf/folder
make
sudo make install

To make sure the module gets loaded and the fan control is enabled, do the following:

echo "acerhdf" | sudo tee -a /etc/modules
sudo touch /etc/modprobe.d/acerhdf.conf
echo "options acerhdf kernelmode=1" | sudo tee -a /etc/modprobe.d/acerhdf.conf
sudo modprobe acerhdf

That will take care of loading the module when starting the laptop and automatically enable the fan control. After doing that, you should already be enjoying silent fan operation. You can also add, to the /etc/modprobe.d/acerfhdf.conf the values fanon= and fanoff=, followed by a value. For example: fanon=60000 fanoff=52000 will turn the fan on when it reaches 60ºC and will shut it down when it reaches 52ºC.

Brightness:

Issue: when changing the brightness using the FN+arrow keys, it will jump 2 levels instead of one.
Solution: add the following into /etc/rc.local, before exit 0 and without quotes: "echo N > /sys/module/video/parameters/brightness_switch_enabled".

Integrated mic:

Issue: the internal microphone is not working. Playing with alsamixer doesn't solve this, all you can hear is noise.
Solution: None at the moment. There's a thing you can try for Skype, though. Do the following, after installing skype from skype.com:

sudo touch /usr/local/bin/skype
sudo chmod +x /usr/local/bin/skype
gksudo gedit /usr/local/bin/skype

There, paste the following, save and close:

#!/bin/sh 

/bin/sh -c "PULSE_SERVER=127.10.10.1 /usr/bin/skype"

After that, you can play a bit with the mic settings under alsamixer and try skype. It shoud kind of work, but there's still some static noise.

Debugging:

One of the attached files contains CheckPowerSaving.sh . This script should help you debugging and will show you what values are being applied. To run it: cd to the folder where the unzipped file is and then sudo ./CheckPowerSaving.sh. If you need help you can attach the output here.

Next to be done:

• Enable undervolting (nothing until Lucid comes out AND the phc repos are running for lucid).

Changelog

• 20/04/2010: added automated install script.
• 16/04/2010: updated for Lucid.
• 29/12/2009: updated version of acerhdf, added blacklist acer-wmi to blacklist (thanks to all who reported)
• 05/12/2009: acerhdf version 0.5.21 now includes BIOS definitions for acer 1410/1810T(Z) and Packard Bell Dot M/U in v3303 and 3120. Audio alternative solution is now the recommended solution (thanks to iiamjon for trying and reporting)
• 02/12/2009: added more acerhdf bios definitions and changed acerhdf enabling. Thanks to teprrr.
• 29/11/2009: added internal microphone fix and BIOS v3303 to acerhdf fix. Also added 1410/1810 clones notice and the Packard Bell Dot M/U definitions to acerhdf fix section.
• 19/11/2009: added noatime,nodirtime to remount filesystem. This should lower disk write access: Linux on Acer 1410, 1810TZ and 1810T. Thanks to tdavis.
• 15/11/2009: Initial post

Thanks

• tdavis, for the wake on lan tip and adding the 11,6" acer series into acerhdf
• teprrr, for the acerhdf modprobe tip and bios definitions
• laramichaels1978, from ubuntuforums, for detecting some errors and suggesting to add the dirty_expire_centiseconds option

[PatrickVogeli]

ORIGINAL POST, JAUNTY:

Hi there all,

I start this thread hoping to help everyone who uses linux in setting up their little timeline to work as good as possible and optimize battery life. I run ubuntu 9.10 64 bits nearly trouble free.

This guide is also posted at the Ubuntu forums.

Packard Bell / Gateway clones:
This guide has also been tested on a Packard Bell Dot M/U with bios v3303, and it should also work on the Gateway clone. If you have a 1410/1810 and something doesn't work, please report back.

Working after a standard Ubuntu 9.10 install:

- Graphics
- Hibernate / suspend
- Audio out, speaker mutes when pluging in headphones. Good volume.
- Networking, both wireless (intel wifi 1000) and wired (the atheros gigabit)
- FN +:
· F4, suspends fine
· F6, monitor goes black
· F7, touchpad on / off
· F8, mute
· F9, Bloq Num
· RePag: Home
· AvPag: End
· Up: increase volume
· Down: decrease volume
· Righ: increase brightness: skips steps.
· Left: decrease brightness: skips steps.
· J,K,L, etc: numeric keyboard ok.

What's not working:

- Audio in: the integrated mic doesn't work.
- FN + F5: not recognised, doesn't toogle displays
- Wireless power saving

Power saving tips:

By default, an ubuntu install won't take too much care of saving power, which is very important in an ultra mobile laptop. You can easily setup the system to enter some power saving modes, specifically the sata controller and the sound chip.

I've setup a script which will take care of making the devices entering the power saving mode when the laptop is on battery.

#!/bin/sh
  # Make sure brightness switch enabled stays on N, even on resume.
  echo N > /sys/module/video/parameters/brightness_switch_enabled
  # Disable wake on lan
  ethtool -s eth0 wol d

# Go fast on AC power.  Similar to default Ubuntu settings
if on_ac_power; then
  # Remount ext3 filesystems so the journal commit only happens every 60
  # seconds. This reduces disk activity.
  mount -o remount,commit=5,atime,diratime /
  mount -o remount,commit=5,atime,diratime /home

  # Set SATA back to normal operation
  for foo in /sys/class/scsi_host/host*/link_power_management_policy;
    do echo max_performance > $foo;
  done

  # Manually set the wifi driver to no power savings.
  # broken in 2.6.31 kernel
  # iwconfig wlan0 power off

  # Set kernel dirty page value back to default
  echo 10 > /proc/sys/vm/dirty_ratio
  echo 5 > /proc/sys/vm/dirty_background_ratio
  echo 600 > /proc/sys/vm/dirty_writeback_centisecs 

  # Disable Intel HD audio power saving:
  echo 0 > /sys/module/snd_hda_intel/parameters/power_save

else # Save power
  
  # Change the ext3 commit times to 10 minutes.  Reduces disk activity
  # disable disk writes when reading
  mount -o remount,commit=600,noatime,nodiratime /
  mount -o remount,commit=600,noatime,nodiratime /home
  
  # Set SATA to save power
  for foo in /sys/class/scsi_host/host*/link_power_management_policy;
    do echo min_power > $foo;
  done

  # Manually set the iwl3945 driver to power savings.
  # broken in 2.6.31 kernel
  # iwconfig wlan0 power on

  # Reduce disk activity by waiting up to 10 minutes before doing writes
  echo 90 > /proc/sys/vm/dirty_ratio
  echo 1 > /proc/sys/vm/dirty_background_ratio
  echo 60000 > /proc/sys/vm/dirty_writeback_centisecs

  # Enable Intel HD audio power saving:
  echo 10 > /sys/module/snd_hda_intel/parameters/power_save
fi

To install this power saving script, do the following:

gksudo gedit /etc/pm/sleep.d/15_saving
# Paste the script above into the file, save and close
sudo chmod +x /etc/pm/sleep.d/15_saving
sudo ln -s /etc/pm/sleep.d/15_saving /etc/pm/power.d/

Next, let's configure gnome-power-manager, under System -> Preferences -> Power management:

- Hard drive power saving: in the battery tab tick on "Reduce hard drive revolutions when possible"
- Battery tab: tick on reduce brightness and dim display.
- AC and Battery tab: configure what to do when closing the lid and what to do on very low battery remaining.
- General tab: configure what to do when pressing the power button and sleep button (Fn+f4).
- General tab: configure when to show the battery icon.

Lm-profiler:
Last, but not least, we'll run lm-profiler to start / stop services when running on battery. To do that, disconnect from the mains and open a terminal (Aplications -> Accessories -> Terminal) and run sudo lm-profiler. It will run for 10 minutes and, when finished, it will ask what services to disable / enabled. You can safely disable cron, anacron and atd, if you don't use them. If you don't know what those are, you can dissabled them. If you never use a printer, or you only use it when connected to the mains, you can also disable cups. If in doubt, don't disable and ask here.

Issues:

Hibernate/resume:

Issue: after hibernating or suspending, the computer won't wake up properly.
Solution: gksudo gedit /etc/modprobe.d/blacklist.conf to edit the file and add the following (without quotes): "blacklist acer-wmi"

Fan:

Issue: the fan is controlled by the BIOS, and is running too loud and too often.
Solution: the solution is installing an update acerhdf module. Download the laster version from here (0.5.22). If you are using BIOS version 3120 or 3303, you can skip patching the module and can directly go on how to install and activate. If you have a BIOS different from that, you'll have to patch it adding your BIOS version. Unpack and look for the acerhdf.c file. In this file, look for the acer 1410 section:

/* Acer 1410 */
{"Acer", "Aspire 1410", "v0.3120", 0x55, 0x58, {0x9e, 0x9e, 0x00} },

We have to add definitions for the Acer 1810T(Z), and also will add some more BIOS versions for the 1410:

{"Acer", "Aspire 1410", "v0.3108", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1410", "v0.3113", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1410", "v0.3115", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1410", "v0.3117", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
/* Acer 1810T */
{"Acer", "Aspire 1810T", "v0.3108", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810T", "v0.3113", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810T", "v0.3115", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810T", "v0.3117", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
/* Acer 1810TZ */
{"Acer", "Aspire 1810TZ", "v0.3108", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810TZ", "v0.3113", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810TZ", "v0.3115", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Acer", "Aspire 1810TZ", "v0.3117", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
/* Packard Bell clone */
{"Packard Bell","DOTMU","v0.3108", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Packard Bell","DOTMU","v0.3113", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Packard Bell","DOTMU","v0.3115", 0x55, 0x58, {0x9e, 0x9e, 0x00} },
{"Packard Bell","DOTMU","v0.3117", 0x55, 0x58, {0x9e, 0x9e, 0x00} },

Save and close. Let's go on into compiling it:

cd /to/the/acerhdf/folder
make
sudo make install

To make sure the module gets loaded and the fan control is enabled, do the following:

echo "acerhdf" | sudo tee -a /etc/modules
sudo touch /etc/modprobe.d/acerhdf.conf
echo "options acerhdf kernelmode=1" | sudo tee -a /etc/modprobe.d/acerhdf.conf
sudo modprobe acerhdf

That will take care of loading the module when starting the laptop and automatically enable the fan control. After doing that, you should already be enjoying silent fan operation.

Brightness:

Issue: when changing the brightness using the FN+arrow keys, it will jump 2 levels instead of one.
Solution: add the following into /etc/rc.local, before exit 0 and without quotes: "echo N > /sys/module/video/parameters/brightness_switch_enabled".

Wireless power saving:

Issue: in kernels from the 2.6.31 series, wireless power saving in intel wireless drivers was dissabled.
Solution: (please, first look at the Alternative Solution below) install updated drivers. the method I used, is compiling and installing the latest intel wireless drivers from the 2.6.32.2 kernel. To do this, download the latest wireless backports drivers from here (compat-wireless-2.6.32.2.tar.bz2, updated). Unpack them and, to compile and install:

cd /to/compat/wireless/folder
scripts/driver-select iwlwifi
make
sudo make install
sudo make unload
sudo modprobe iwlagn

Alternative solution: not tested by me. Install the linux-backports-modules-wireless-karmic-generic package and reboot. If it doesn't work, uninstall all linux-backports-modules-wireless packages using Synaptic and reboot.

Now you'll be using the newest available intel wireless driver, where power saving works again. You can enable power saving by doing "sudo iwconfig wlan0 power" on or disable doing "sudo iwconfig wlan0 power off".

Now you can also uncomment the power saving lines in /etc/pm/sleep.d/15_saving script, so that the wireless enters power saving automatically when on battery and exits when pluging in the laptop again.

Integrated mic:

Issue: the internal microphone is not working. Playing with alsamixer doesn't solve this, all you can hear is noise.
Solution: Install the linux-backports-modules-alsa-karmic-generic packages. Using this solution, when a new kernel appears, it will also take care of reinstalling the newer alsa modules. Should it not work and/or you want to revert changes, uninstall all the linux-backports-modules-alsa packages using synaptic and reboot.
Alternative solution: download, compile and install a newer Alsa driver. Using this solution, everytime a new kernel is installed, you'll have to repeat this for the new kernel. Go to the Alsa project webpage and download the lastest available alsa-driver. At the time of writing (29/11/09), that's 1.0.21. Once you have it, uncompress it and do the following:

cd /to/alsa/driver/folder
./configure --with-cards=hda-intel --prefix=/usr
make
sudo make install

After rebooting, your internal microphone should be working. I've tried it with the sound recorder program under Aplications -> Sound & Video menu. Quality doesn't seem to be great, maybe playing with settings will help. If someone has some tested tips (same fix, same machine), I'll add them. Thanks.

Next to be done:
- Enable undervolting

Changelog
29/12/2009: updated version of acerhdf, added blacklist acer-wmi to blacklist (thanks to all who reported)
05/12/2009: acerhdf version 0.5.21 now includes BIOS definitions for acer 1410/1810T(Z) and Packard Bell Dot M/U in v3303 and 3120. Audio alternative solution is now the recommended solution (thanks to iiamjon for trying and reporting)
02/12/2009: added more acerhdf bios definitions and changed acerhdf enabling. Thanks to teprrr.
29/11/2009: added internal microphone fix and BIOS v3303 to acerhdf fix. Also added 1410/1810 clones notice and the Packard Bell Dot M/U definitions to acerhdf fix section.
19/11/2009: added noatime,nodirtime to remount filesystem. This should lower disk write access. More info here. Thanks to tdavis
15/11/2009: Initial post

Thanks
tdavis, for the wake on lan tip and adding the 11,6" acer series into acerhdf
teprrr, for the acerhdf modprobe tip and bios definitions

[der_mali]

Thanks a lot!
Added to Timeline Tweaks.

[tdavis]

does ubuntu turn off atime updates by default?

If so, then doing a remount with noatime will help let the drive spin down.

Also, how about laptop_mode? (ie, /proc/sys/vm/laptop_mode) What does ubuntu do with it? Fedora doesn't touch it.. ie, read Documentation/laptops/laptop-mode.txt in the kernel..

[arkusuma]

Wow, great tips...
I'm waiting for your 1410 undervolting guide.

Thanks.

[PatrickVogeli]

hi,

I don't know about noatime.. what does it exactly do?

As for laptop mode.. I think in ubuntu in only touches the hard drive, even though you can configure ir to do a lot of other things, but since gnome-power-manager now includes an option to reduce disk revolutions when possible, I removed the laptop mode stuff. I don't know if they did the same or not, though.

[tdavis]

hi,

I don't know about noatime.. what does it exactly do?

Every file created in a Unix style filesystem (note - msdos/vfat doesn't support this), you get 3 timestamps.

ctime ie, create time
mtime ie, modification time,
atime ie, access time.

Simply reading the contents of a file, causes a write to the filesystem to update the access time.

By default, atime updates are on. It's designed to allow a backup/hierachial storage system to move files around by access patterns (ie, from fast storage to slow storage).

Turning off atime at the mount turns off this write, which gives the hard drive a better chance of spinning down (or, in the case of a flash based device, long life by cutting writes down).

Like I posted in another thread, doing:

/bin/mount -o remount,noatime,nodiratime /

turns off the write; editing your /etc/fstab and adding the noatime,nodiratime to the filesystem mount makes it permanent.

[PatrickVogeli]

I assume that, after doing

/bin/mount -o remount,noatime,nodiratime /

I can reenable atime using this one:

/bin/mount -o remount,atime,diratime /

Is this correct??

[tdavis]

I assume that, after doing

/bin/mount -o remount,noatime,nodiratime /

I can reenable atime using this one:

/bin/mount -o remount,atime,diratime /

Is this correct??

That is correct, it will turn it back on.

[teprrr]

Hello there and thanks for the tips!

Just wanted to notify you that newer kernels may not work without "hacks" due to some changes. The BIOS is apparently broken/reports wrong information and due to a change in kernel it'll cause a kernel panic.

If there's no fix available, iommu=soft or intel_iommu=off, can be applied to kernel options to make it go away. For more details see https://bugzilla.redhat.com/show_bug.cgi?id=533952

Btw, does/should brightness setting work with acer-wmi or the general one? See 'dmesg|grep acer' to see if it reports that it must be controlled by a generic driver, no idea if it should but at least that's what it does here...