Emulating the XO/Help and tips: Difference between revisions

Latest revision as of 16:15, 8 February 2011

For current information on emulation of OLPC software images, see Emulating the XO

WARNING:
The content of this section is considered
DEPRECATED and OBSOLETE
It is preserved for historical or documenting reasons.

When it comes to emulating systems like the XO, sometimes it seems like technology only manages to get us 95% of the way there--the last 5% an assortment of mystical incantations and other superstitious activities just to confuse the uninitiated. This page is a humble attempt to take some of the magic and mystery away from this sufficiently advanced science.

Please remember to end your comments with ~~~~, which is replaced by a time stamp when you save the page. Without them, notes that are months old and obsolete look the same as notes added yesterday.

Bear in mind that some of the information on this page is obsolete, and some of it only applies to certain XO disk images.

How to

Keyboard and buttons

The XO has dedicated keys on the keyboard for Sugar features such as the Home view, the Neighborhood, and showing/hiding the frame; it also has buttons around the screen for screen rotation and gamepad controls. Some of these correspond to function keys on regular keyboards, and there are keystroke combinations for others; see Keyboard shortcuts.

Change the keymapping to your local keyboard layout

To change the keyboard layout when you are using an Emulation do:

1. enter Console (Alt-Ctrl-F1)
2. login as root (just hit RETURN, no password needed)
3. type

loadkeys xy

where xy is your keyboard layout shortcut, e.g. "de" for german layout.

(be careful: as you havn't changed your keyboard layout when you type the command, you might have to hit the key "z" to get an "y" and/or the key "q" to get an "a".)

4. edit /etc/sysconfig/keyboard (this changes the keyboard layout within SUGAR)

vi /etc/sysconfig/keyboard

"a" starts edit-mode (insert after cursor)

change "us" to your keycode two times.

leave edit-mode (ESCAPE)

type ":wq" and hit Enter to write the changes and quit the editor

If you produced a chaos and want to quit without writing the changes, type ":q!"

You find additional information about the codes used in /etc/sysconfig/keyboard in the Manufacturing Data page.

5. edit /etc/rc.d/rc.local (this changes the keyboard layout permanently for the console)

vi /etc/rc.d/rc.local

"a" starts edit-mode (insert after cursor)

move the cursor to the end of the file, hit RETURN to create a new line.

type "loadkeys de" (or whatever keycode you want)

leave edit-mode (ESCAPE)

type ":wq" and hit Enter to write the changes and quit the editor

If you produced a chaos and want to quit without writing the changes, type ":q!"

If you don't know the mapname/code for your keyboard layout, go to /lib/kdb/keymaps, switch to the subdirectory that covers your architecture (eg "i386" for Intel-platforms), and then enter the subdirectory which covers your keyboard type (look at the first six letters on the upper left of your keyboard to distinguish the "azerty", "qwerty" or "qwertz" layout type). In the subdirectory, you find some keymaps for your keyboard layout - find out which one fits your keyboard exactly. The keymap code is the filename without "map.gz".

Valid examples (among others) are:

"by", "cf", "cz", "dk", "emacs", "es", "et", "fi", "gr", "hu101", "il", "is-latin1", "it", "jp106", "ko", la-latin1", "lt", "nk", "nl", "no", "pc110", "pl", "pt", "ro", "ru", "se-latin1", "sk-qwerty", "sr-latin", "sv-latin", "trq", "ua", "uk", "us" (QWERTY)
"cz-us-qwertz", "de", "croat", "fr", "fr_CH", "sg", "sk-qwertz", "slovene", "hu" (QWERTZ)
"azerty", "be-latin1", "fr", "wangbe" (AZERTY)

If those examples don't fit your keyboard layout exactly, please have a look into the directories for yourself to look for alternatives or define your own keymap (see http://wiki.linuxquestions.org/wiki/Configuring_keyboards#The_Loadkeys_Method for instructions)

Sending Ctrl-Alt combos in Qemu (or Q.app)

According to (now obsolete) Sugar Instructions you need to "hold down Ctrl+Alt+F1 to leave the Sugar screen and return to the login prompt" and then "you can return to Sugar with Ctrl+Alt+F7". Unfortunately for me the "Ctrl+Alt" action seems to be grabbed by the Q.app "mouse pointer ungrab" functionality.

Under Linux, this will be grabbed by the X server running on your computer, and not the one running in the emulator, and will switch your own computer to a terminal.

The other method(s) suggested for opening a terminal activity didn't work for me either (OLPC build 239). I eventually discovered that Q.app actually has a "Monitor" accessible by "ctrl-alt-2". When in this monitor mode you can send key-presses directly to the OLPC emulation by using the "sendkey" command. For example:

  sendkey ctrl-alt-f1       # to switch to the shell
  sendkey ctrl-alt-f7       # to return to Sugar

Note: you will need to exit the monitor mode and return to the emulated machine by pressing "ctrl-alt-1" once you type either of the above commands.

Note: you type the name of the keys to send, you don't actually press the keys.

Get a login prompt

If you started qemu with the -serial `tty` argument, you can simply use that login prompt (Linux only, doesn't work on Windows).

Otherwise, pressing ctrl alt 3 will bring up the console. (But then you can't cut and paste from/to the host machine).

You can alternatively use the Terminal activity.

Login as root

#Get a login prompt.

In post-650 builds, do not directly login as root, but first as user 'olpc'. The password for user olpc on fresh xo/qemu images is empty. (Pre-650 you could login as root with an empty password by default.)

Then "sudo su -" to get a root prompt.

Change the root password

#Login as root. Then:

passwd

Complaints about "BAD" passwords won't stop things from working.

Speed

Does my qemu have kqemu?

Does the version of the QEMU support KQEMU? Type ctrl+alt+2 and type info kqemu. Use ctrl+alt+1 to return to OLPC screen.

On x86_64 you must run qemu-system-x86_64 instead of qemu.

Giving the -kqemu-kernel argument if kqemu is not supported will cause a one-line warning to go by as qemu starts up:

Could not open '/dev/kqemu' - QEMU acceleration layer not activated

I run 'sudo qemu -kqemu-kernel ...' and this error doesn't appear. Does it mean it's being used? I haven't measured time differences yet, but it feels faster to boot and use.HoboPrimate 17:56, 6 August 2007 (EDT)

kqemu impact

After installing kqemu and modprobe'ing, I get a 3x speedup in booting (to 45 sec), and a 5x in starting the webrowser (to 7 sec). It actually feels usable. MitchellNCharity 17:25, 13 May 2007 (EDT)

Coping with Slowness

It is possible for the OLPC image to boot successfully and load the Sugar UI in the emulator but then be too slow to successfully load any activities.

For example, between build 239 and build 303 activity loading slowed enough for me (Qemu / 1.6GHz G4 PPC / OS X) that no activities loaded successfully. Symptons include messages in /home/olpc/.sugar/default/logs/shell.log like this:

DEBUG - Shell.start_activity
DEBUG - Activity f4a9f5322b49dcc3364a4eca9b13633c0ce1868e (org.laptop.ChatActivity) launching...
DEBUG - Activity f4a9f5322b49dcc3364a4eca9b13633c0ce1868e (org.laptop.ChatActivity) launch timed out
STDERR - Introspect error: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.

DEBUG - Couldn't create activity f4a9f5322b49dcc3364a4eca9b13633c0ce1868e (org.laptop.ChatActivity): Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
ERROR - Model for activity id f4a9f5322b49dcc3364a4eca9b13633c0ce1868e does not exist.
DEBUG - Activity f4a9f5322b49dcc3364a4eca9b13633c0ce1868e (org.laptop.ChatActivity) launching...
DEBUG - Activity f4a9f5322b49dcc3364a4eca9b13633c0ce1868e (org.laptop.ChatActivity) finished launching

Another sympton is the flashing activity load icon appearing in the donut for a length of time and then disappearing without the activity loading. (Although this can also be caused by other issues such as uncaught programming errors.)

These failures are due to two timeouts values configured in the system, one in Sugar and one in D-Bus. If you're more patient than OLPC/Sugar is by default then it's possible to tweak these values to enable activities to eventually load:

D-Bus

Insert the following line in /etc/dbus-1/session.conf below the </policy> tag:

  <limit name="service_start_timeout">120000</limit>

This means D-Bus will wait 120 seconds before giving up--the icon will still disappear from the donut but eventually the activity will load. (Strictly speaking this setting might really need to be in session-local.conf. See man dbus-daemon.)

Sugar

To ensure the flashing activity load icon appears in the donut longer the following untested change should work:

In shell/model/homeactivity.py replace:

self._launch_timeout_id = gobject.timeout_add(20000, self._launch_timeout_cb)

with (for example) this:

self._launch_timeout_id = gobject.timeout_add(120000, self._launch_timeout_cb)

As far as I can tell this only has a cosmetic impact and activities should still load without it.

More often than not, technology manages to get us 95% of the way... being the last 5% a mix of magical incantations, rituals and other esoteric activities only clear to the initiated. This page tries to take some of the magic away from the sufficiently advanced science

  If you want to use nano for system file edits,
  make sure line wrap is disabled by Alt-L 
  (or look here for its documentation).

My emulator is very slow

Are you using the kqemu or qvm accelerator modules? You do have to have administrator rights to install the services. QEMU manager (in Windows) knows to start these services according to your profile settings. See Qemu on Windows and QEMU Home Page

Display

Font Size correction

You will want to edit /etc/X11/xorg.conf and apply the changes suggested in (Trac #3681) to get the fonts to look bigger and nicer in emulation: (Vorburger 13:35, 7 October 2007 (EDT))

Edit xorg.conf

  Ctrl-Alt-3
  nano /etc/X11/xorg.conf

Add a new section "monitor"

  Section "Monitor"
          Identifier "Monitor0"
          DisplaySize 153 115
  EndSection

Add a "Monitor" line to the "Screen" Section

  Section "Screen"
       ...
       Monitor "Monitor0"
  EndSection

Restart X [ kill it and let init respawn it. ]

  killall -i X

Fullscreen

If you run qemu on a physical 1024x768 display (e.g. a laptop with 1024x768 LCD), you get a MUCH more "natural" experience if you switch qemu to fullscreen: Add "-full-screen" as argument to qemu start-up, and/or press Ctrl-Alt-F on a running qemu to toggle. (Vorburger 13:35, 7 October 2007 (EDT))

Development

Use the -devel_ext3.img xo disk image

You need a "*-devel_ext3.img" image, rather than a standard (non-devel) one. The -devel image has extra software like sshd and wget. The code changes rapidly, so you probably want LATEST rather than LATEST-STABLE.

Communicating between host and xo image

Check networking

Make sure networking is working. In short, an "ifconfig" should show inet addr:10.0.2.15 on eth0, you should be able to do a "ping 10.0.2.2" (that's how the host is visible) and have a working e.g. "wget http://wiki.laptop.org/" from CLI before going any further.

Recent builds (i.e. 613) work out of the box IFF you pass the correct qemu start-up parameters (see Emulating the XO/Quick Start). If not, you can try a manual "ifup eth0", but as of build 613 there will be other problems (X/X11/Sugar start-up) if networking is not working during start-up.

Vorburger 04:14, 7 October 2007 (EDT)

SSH into qemu

#Change the root password
Add the argument -redir tcp:2222::22 whenever you run qemu. 22 is the ssh port (on the guest). 2222 is a semi-arbitrary port on the host, which gets mapped to it. If you run a second image simultaneously, you could use 2223::22 for it.
You can now log into the laptop image, from your real machine, using ssh. And you can use scp, etc.

ssh -o NoHostAuthenticationForLocalhost=yes -p 2222 root@localhost
scp -o NoHostAuthenticationForLocalhost=yes -P 2222 filefoo.py root@localhost:/usr/share/activities/Your.activity
scp -o NoHostAuthenticationForLocalhost=yes -P 2222 -r Your.activity/ root@localhost:/usr/share/activities/Your.activity

Unfortunately, you have to keep typing the password, unless you have set up a key.

SSH into qemu, using a key

Setting up a key means you don't have to keep typing the password.

The -devel xo .img is already running sshd.

Create a key pair if you don't already have one:

ssh-keygen -N '' -t rsa -f ~/.ssh/id_rsa   # If it asks you Overwrite?, say NO!.  You already have one.

This creates a no-passphrase key pair. Which is fine for using with the xo image (no-one is trying to break into the xo from your machine;), but you shouldn't later use this weak key on other, more important systems.

Copy the public key onto the xo image:

#Change the root password if you haven't already.

scp -o NoHostAuthenticationForLocalhost=yes -P 2222 ~/.ssh/id_rsa.pub root@localhost:~/

#SSH into qemu

Inside ssh, do:

mkdir ~root/.ssh
mkdir ~olpc/.ssh
cat id_rsa.pub >> ~root/.ssh/authorized_keys
cat id_rsa.pub >> ~olpc/.ssh/authorized_keys

Now you can ssh into the xo image without typing a password.

You may need to change the permissions of the authorized_keys file like this:

chmod g-w ~root/.ssh/authorized_keys
chmod g-w ~olpc/.ssh/authorized_keys

SSH into qemu, without having to specify the user or port

Setup a ssh config entry on your host to simplify using ssh. The following steps are all performed on the host.

Create a config file if you don't already have one:

touch ~/.ssh/config

Add a section for your host (vi ~/.ssh/config or nano ~/.ssh/config) :

Host olpc
       User root
       Port 2222
       Hostname localhost

You can now just use the alias olpc to use ssh/scp without specifying the user or port

ssh olpc

or

scp somefile olpc:

Comfortably transfer Files between Host and XO

To transfer Files between Host and XO, once you have set-up a root passwd and added the argument -redir tcp:2222::22 whenever you run qemu as described above, the easiest is to use scp with a graphical scp client. This will allow you to easily "browse" and "explore" the XO's file system.

ToDo: On Linux, Nautilus und Konqueror can natively do scp as well; you probably just type scp://localhost:2222/ (or fish://localhost:2222/, or sftp://localhost:2222/ ?) in the address bar, but I haven't tested this.

On Windows, use WinSCP from http://winscp.net/eng/download.php and connect as root to localhost port 2222.

PS: And while we're on tools for Windows... use Putty from http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html to SSH (localhost:2222) from Windows into your XO, not Cygwin. Putwin will emulate the terminal correctly by default, give you colors, scrolling and copy/pasting easily work, etc.

Vorburger 04:23, 7 October 2007 (EDT)

Pull things from a webserver

If you don't want to deal with ssh, and have a webserver, you might simply download stuff using wget or the Browser activity.

Get an xterm from the xo

Use -X

ssh -X -o NoHostAuthenticationForLocalhost=yes -p 2222 root@localhost
...
xterm&

However, there are security vulnerabilities associated with -X.

Miscellaneous

Under QEMU the Laptop image can see the host as IP address 10.0.2.2 .

Doables:

Perhaps describe using samba and qemu's tftp.
Describe passphrase avoidance if you already have an id. Is giving folks a no-passphrase id just setting them up for future problems? What's the right thing here?

Running sugar activities from shell

Running sugar activities from the command-line, instead of via the gui, can be useful when debugging.

Log in as root, then:

su olpc
grep export /usr/bin/sugar > /tmp/env
source /tmp/env

You can then run activities:

sugar-activity web

Restart sugar

Sugar notices new activities, and changed activity icons, only when it starts.

To restart sugar, you can do any of:

Restart qemu
Kill X using killall: As root, run

killall -i X

Kill X using the qemu console (see #sendkey):

sendkey ctrl-alt-backspace

Get 1200x900 resolution

Qemu does not currently support 1200x900 (though the cvs version is said to, via -vmwarevga). It defaults to 1024x768. Which is what the laptop's X and cairo see. So code you write assuming 1200x900, gets an unexpected down-scaling. Cairo make-it-smaller scaling is currently much faster than its make-it-bigger, so the performance impact may not be large. But if you were hoping to do nifty things with 200bpi, you need the CVS version. Or maybe use 1280x1024, and only use part of the screen? MitchellNCharity 21:16, 6 June 2007 (EDT)

See #Run a Xephyr remote X display for a workaround. MitchellNCharity 10:48, 23 June 2007 (EDT)

Qemu does indeed support 1200x900, with the help of a special modeline. Here's the relevent parts extracted from my xorg.conf :

Section "Device"
	Identifier	"Carte vidéo générique"
	Driver		"cirrus"
	BusID		"PCI:0:2:0"
EndSection
Section "Monitor"
	Identifier	"Moniteur générique"
	Option		"DPMS"
	HorizSync	28-51
	VertRefresh	43-60
	Modeline 	"1152x864@43" 55.75 1152 1184 1392 1424 864 883 889 908
	Modeline 	"1200x900@43" 60.82 1200 1232 1456 1488 900 919 926 946
EndSection
Section "Screen"
	Identifier	"Écran générique"
	Device		"Carte vidéo générique"
	Monitor		"Moniteur générique"
	DefaultDepth	16
	SubSection "Display"
		Modes	"1200x900@43" "1152x864@43" "1024x768"
	EndSubSection
EndSection

Hklv 18:13, 5 April 2008

Run a Xephyr remote X display

You can use Remote Display to run X in a window on your host machine, rather than in the qemu window. Xephyr might also be used to get 1200x900 with a sugar-jhbuild sugar.

Once qemu supports 1200x900, or if you are using a different emulator, this may not be of interest.

In qemu, as root,

The first time:

Give olpc a password

passwd olpc

disable S98NetworkManager for rc3 if you earlier needed to do this for normal rc5.

mv /etc/rc3.d/S98NetworkManager /etc/rc3.d/DISABLED-S98NetworkManager

Every time:

partially shut down:

init 3

wait a bit, and then turn the network back on:

ifup eth0

On the host, (based on http://etbe.blogspot.com/2007/01/xephyr.html ):

The first time:

give an xauth cookie to olpc and Xephyr

mcookie > xephyr-cookie
export COOKIE=`cat xephyr-cookie`
rm -f xephyr-xauth; echo "add :1 . $COOKIE" | xauth -f xephyr-xauth
ssh -o NoHostAuthenticationForLocalhost=yes -p 2222 olpc@localhost "echo \"add 10.0.2.2:1 . $COOKIE\" | xauth"

Every time:

run Xephyr

Xephyr :1 -auth xephyr-xauth -reset -screen 1200x900x8 -dpi 200

and in another window, start sugar

ssh -o NoHostAuthenticationForLocalhost=yes -p 2222 olpc@localhost

and then as olcp:

DISPLAY=10.0.2.2:1 sugar

Ideally we would run /bin/sh .xinitrc, instead of sugar, but it currently crashes Xephyr repeatedly. The right thing is probably to extract the lines Xephyr is ok with, like setting keyboard repeats, and check that dropping the others doesn't lose something important.

Only because it might be easier on non-linux platorms, I note: A simpler, but much less secure, and probably slower (-X uses encryption) alternative is to run Xephyr with the -ac argument (disabling access control! Don't do this unless you really trust your firewall and local environment). And then in another window on the host, run xterm -display :1 -e ssh ... .xinitrc. Interestingly, this approach didn't require repeatedly restarting Xephyr.

Switching to a different presence server

Here we switch to olpc.collabora.co.uk:

cp -p /home/olpc/.sugar/default/config /home/olpc/.sugar/default/config.old
gawk '/^server =/ {print "server = olpc.collabora.co.uk"} !/^server =/ {print}' /home/olpc/.sugar/default/config.old > /home/olpc/.sugar/default/config

Then #Restart_sugar.

Running multiple qemus

You can run multiple qemus at the same time. Each must have its own disk image.

There are a couple of options:

1. Just run them as you would individually.

This is easiest, and sugar Presence Service and tubes seem to work fine. Even though the copies all think they have the same ip address and mac.

2. Give the instances distinct macs and ips.

Illustrate... MitchellNCharity 23:45, 27 June 2007 (EDT)

3. Start a virtual network.

Eg, see http://olpcaustria.org/mediawiki/index.php/Devserver . Instances must be able to see the internet for Presence Service to work.

Are there any advantages to doing a VDE versus option 2? MitchellNCharity 23:45, 27 June 2007 (EDT)

Allows incoming connections, by avoiding qemu's default firewall. What else? MitchellNCharity 12:12, 28 June 2007 (EDT)

Installing software on the -devel image

The -devel_ext3 images have yum to install normal fedora x86 .rpm's.

If an olpc repository is down (eg olpc_development) one can still run yum by saying yum install package --disablerepo=olpc_development.

There is little free disk space on the -devel images, so you will need to #Expand a qemu image to install anything large.

Logging boot messages

WARNING: This disables (at least on Windows) the Ctrl-Alt-3 console (you get a "parallel0 console" instead) !!!

For Linux:

qemu -serial stdio -hda olpc-redhat-stream-development-ext3.img | tee boot.log

For Windows:

qemu.exe -serial file:boot.log -hda olpc*.img

The kernel params in /boot/grup/menu.lst are already set to send to console IO to both the screen and serial ( console=ttyS0,115200 console=tty0), so -serial stdio is all it takes to have it sent to stdout.

PS: Qemu on Windows doesn't like "-serial stdio", thus the "-serial file:boot.log" - might actually work on Linux, too?

PPS: Repeating warning - this disables (at least on Windows) the Ctrl-Alt-3 console (you get a "parallel0 console" instead) !!!

Cut and paste text from qemu

One simple approach is to login in the window from which qemu was started. This window is in the X of the host, but has the shell in qemu. So you can cat the text, and cut and paste it.

x2x might be another alternative. We should explore and document it. http://borderworlds.dk/blog/20070224-00.html MitchellNCharity 15:45, 2 October 2007 (EDT)

Mounting a qemu image (to directly manipulate its filesystem)

You can mount a ext3.img, to directly manipulate its filesystem. Caution: running qemu on it while it's mounted is said to be bad.

file olpc-redhat-stream-development-ext3.img

will say something like

olpc-image/olpc-redhat-stream-development-ext3.img: x86 boot sector; partition 1: ID=0x83, starthead 1, startsector 62, 984994 sectors, extended partition table (last)\011, code offset 0x48

Here the startsector is 62. Multiply it by 512 to get the mount offset (here 62*512=31744).

mkdir tmp_img
sudo mount -o loop,offset=31744 olpc-redhat-stream-development-ext3.img tmp_img

Expand a qemu image

With N changed to the desired size in MB: (If on Windows, get Cygwin and install a dd; that works! ( The Qemu Manager allows a volume/drive image to be created and then accessed as e.g. /dev/hdb ))

dd if=/dev/zero of=laptop.img seek=N obs=1MB count=0

Obtain the gparted .iso LiveCD, from http://gparted.sourceforge.net/livecd.php (~50MB).

qemu -kernel-kqemu -boot d -cdrom gparted-livecd-0.3.4-7.iso laptop.img

Make sure you chose the second option in the Grub boot menu, "GParted-liveCD (Do X Configuration = mkxf86config)", not the default first "... (auto-configuration)".

(Alternatively, with the Qemu Manager, start up a regular image with a second (larger) volume e.g. /dev/hdb, once booted up, copy the original drive (/dev/hda) to the expanded image on /dev/hdb with e.g. "dd if=/dev/hda of=/dev/hdb" then follow the #Enlarging_the_Partition and #Enlarging_the_filesystem instructions...)

Do http://gparted.sourceforge.net/larry/resize/resizing.htm

For more background information, see also: (But you do not have to execute these steps when using gparted)

Emulating the xo's unusual color display

GTK for OLPC links to a patch to Xephyr, which adds a --swizzle argument, which very roughly emulates the appearance of an xo screen.

The patch requires only one small change to apply against the current xserver source (git://anongit.freedesktop.org/git/xorg/xserver). But I've not been able to try compiling it (dependency issues). It might be easier on a distribution which handles source better than fedora, or on fc7. MitchellNCharity 14:13, 23 June 2007 (EDT)

There is now a display simulator for screenshots. MitchellNCharity 19:26, 23 June 2007 (EDT)

To erase the Journal

rm -r ~/.sugar/default/datastore

If using nano (an editor), disable line wrapping

If you want to use nano for system file edits, make sure line wrap is disabled by Alt-L (or look here for it's documentation).

Network startup

Should now "just work".

For the next week or few (Dec 2007), presence service (collaboration and mesh view) in joyride builds wont work out of the box, as they are configured to use a not yet existant ship2.jabber.laptop.org. You might try the currently overloaded and fragile jabber.laptop.org instead. MitchellNCharity 22:46, 14 December 2007 (EST)

Configuration

Altering display size and resolution

If you really can't get 1200x900, you can use 1280x1024 or 1024x768 instead. You can even use 800x600 to perhaps do development on small displays, but the result looks very different than on the real 1200x900.

Setting Framebuffer size

The kernel can be started with a VGA framebuffer of a few sizes. The vga=0x317 option.

You can edit the kernel line in /boot/grub/grub.conf, or at boot time, in the initial blue GRUB screen.

VGA kernel color / resolution table Colors 640x480 800x600 1024x768 1280x1024 256 0x301 0x303 0x305 0x307 32k 0x310 0x313 0x316 0x319 64k 0x311 0x314 0x317 0x31A 16M 0x312 0x315 0x318 0x31B

NOTE: If you don't set the VGA kernel parameter to 0x317 (in order to get a 1024x768 with 64k colors) you will NOT be able to view / use Etoys properly.

This NOTE is old. It may or may not be still true. 0x31A seems to work too. MitchellNCharity 18:56, 8 November 2007 (EST)

Setting DPI and font size for odd display sizes

https://dev.laptop.org/ticket/3681

Altering the desktop resolution on the LiveCd

I am not sure what this (below) does and if reducing the resolution to 800x600 is really a good idea, but what is outlined in https://dev.laptop.org/ticket/3681 seems to help to make things a bit less ugly in Emulation. (Vorburger 07:15, 7 October 2007 (EDT))

This is said to work on the current LiveCd. It might also work in xo/qemu images? MitchellNCharity 13:50, 5 June 2007 (EDT)

Somehow pull up a terminal (there is one easily accessible via the classic Gnome desktop)
Either edit /etc/X11/xorg.conf (example below focusing on the 'Modes' line setting 800x600) OR run system-config-display and select the appropriate resolution from the GUI
Restart the X server with ctrl-alt-backspace (NOTE: This may take some seconds. It will drop back to a login prompt but if you wait it will start up X again, assuming you provided a valid resolution.)

Section	"Screen"
	Identifier	"Screen0"
	Device		"Videocard0"
	DefaultDepth	24
	SubSection	"Display"
		Viewport	0 0
		Depth		24
		Modes		"800x600"
	EndSubSection
EndSection

Problems

Sound doesn't work

Latest images add support of sound. Emulation does not work properly with Tam-Tam, yet, even with kqemu at 2 GHz Pentium4 (performance or insufficient emulation issue?). Maybe somebody could install Csound in host and pipe sound over the virtual network? Windows version can be found in Cecilia and Csound for Windows installer --Tonyv

Keyboard and Mouse don't work

A typical case is that their keyboard and mouse don't work. A solution to the problem is:

Make sure the the window has the focus (label should say QEMU - Press Ctrl-Alt to exit grab).
Start the Terminal Activity, or press Alt + Ctrl + 1 (or Alt + Ctrl + 3) to enter the terminal mode of the OLPC. Notice that QEMu seems to respond better to by pushing first down Ctrl, after Alt and finally the number.
Make sure that you're logged in.
- If not, just hit enter and it'll ask you to.
- Login as root (no password is required)
Type modprobe i8042 (oddly, you may need to try this multiple times before it works, so keep trying!)

Press Alt + Ctrl + 7 to return to the graphical mode of the OLPC.
Your keyboard and mouse should be working fine.
- Usually the result is a continuous series of 1's will flow (as if the key is stuck)
- Just hit any key (to stop it) and delete the offending 1's

Alternatively you can use the developers console and su command. I have not been able to bring up the terminal in most images. Quote from BTest-1_Release_Notes :

Note: this does not work on joyride build 1483. I get FATAL: Module i8042 not found. LinuxMercedes 20:33, 21 January 2008 (EST)

Sugar GUI won't start

If the GUI fails to start, you may have forgotten to choose emulated when you booted, or you may have encountered the "GUI won't start" bug. The "GUI won't start" bug is fixed by reinstalling the hard disk image. (Or it may be because of a bug in the image file, see (Trac #1295) ). In QEMU, delete the .img file (it has become corrupted), and extract the original .img file from the bz2 file, or download the image file again. Upgrading to a later version isn't necessary.

On Ubuntu with Xinerama, mouse behaves strangely and cursor disappears

Try running "export SDL_VIDEO_X11_DGAMOUSE=0" before running Qemu (if you use another shell instead of bash, use something like "setenv SDL_VIDEO_X11_DGAMOUSE 0").[1] MitchellNCharity 15:38, 2 October 2007 (EDT)

On Fedora, "service qemu start" needed?

On fedora linux, to get qemu working, you may have to start the service for it. As root run:

service qemu start

Why would this be needed?? Emulation works without it. And making .exe files self launching seems unfortunate. MitchellNCharity 21:21, 23 May 2007 (EDT)

On Linux, if qemu complains about insufficient space in /dev/shm

then

mount -t tmpfs -o remount,size=144m none /dev/shm

Boot hangs on Debian-derived distros

We have heard multiple people say that QEMU doesn't work with these images on the debian-derived distributions. The symptom is that the kernel hangs during boot. There's a problem with bochsbios version 2.2, version 2.3 works. As a quick fix, apm=off can be added to OLPC kernel arguments.

We have heard multiple people say that QEMU doesn't work with these images on the debian-derived distributions. We also haven't heard of any solutions to these problems. The symptom is that the kernel hangs during boot.

Marcin: On Ubuntu Dapper it hangs with qemu 0.8.0 (from distro), but works with 0.8.1 from i386 binary tarball.

Budgester (I can confirm this situation on Ubuntu Dapper)

Vedran: It also hangs on Debian unstable with qemu 0.8.1-1 (from distro), but works with 0.8.1 from i386 binary tarball.

kevin.mark@verizon.net: It also hangs on Debian unstable with bochs 2.2.6-2 (from distro) the same way it does for qemu as noted above

MikeX: qemu 0.8.1-1 packaged for debian sid amd64 seems to work for me (system boots but sugar hangs, tried with build84).

[2]: It works on Debian Etch with qemu 0.8.2-4 (a little slow but works ok).

Spawn968: Hangs using qemu 0.8.2 with kqemu-1.3.0pre9, but runs fine on qemu 0.8.2 in Ubuntu Dapper.

dilinger: This is not actually a qemu issue; it's a bochsbios issue. Bochsbios 2.2 is broken in this regard; bochsbios 2.3 might work (an sti was added). A quick fix for allowing it to boot is to add 'apm=off' as a kernel argument. Debian bug #363047 has additional details.

Jwaddell:: Thanks Marcin...getting the 0.8.2 binary tarball from the link you provided made the image work under Ubuntu Dapper for me ;)

Tomhannen:: Please could some of you document your successes/failures on this page?

lealcy:: OLPC image doesn't work with Qemu 0.8.2 on Ubuntu 6.10 (Edgy Eft). It freeze in startup process. Check this shot:

http://wiki.laptop.org/go/Image:OLPC-qemu0.8.2-ubuntu6.10.png

Update: With the qemu 0.8.2 downloaded from http://fabrice.bellard.free.fr/qemu/download.html (the binaries) 1b2 loaded to the graphic interface, but I feel the interface a bit unresponsible (maybe an issue by emulation.) Thanks to Fernando <fernandogrd at yahoo dot com dot br> by the Qemu 0.8.2 Ubuntu issue tip.

SandwichButton:: lealcy, try entering the apm=off kernel argument. You need to enter the grub menu, edit the 'for qemu target' option by highlighting it and pressing e. The second line is the kernel arguments you pass at boot time. enter 'apm=off' without the single quotes at the end of the line, hit enter, then press b. It was previously freezing while mounting hda. My machine runs qemu 8.2, edgy 6.10 (w/ updates), and build 185 just fine now.