SteamLink

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SteamLink

About

github ValveSoftware/steamlink-sdk

In the meantime there is a steamlink version in the Raspian repositories.

Shell Access

SteamLink-SDK describes how to gain access to the device via ssh.

Format a USB-Stick with FAT32 and create a non-empty file on a specific path.

   1 lsblk
   2 LABEL="STEAM_HACK"
   3 mkfs.fat -n "$LABEL" /dev/sdc
   4 cd /media/tobias
   5 mkdir "$LABEL"
   6 mount /dev/sdc "$LABEL"
   7 mkdir -p "$LABEL"/steamlink/config/system
   8 echo "Your soul is mine." > "$LABEL"/steamlink/config/system/enable_ssh.txt
   9 umount /dev/sdc
  10 eject /dev/sdc

Reboot SteamLink

Login	`root`
Password	`steamlink123`

~/.ssh/config

   1 host steamlink
   2         user root

Copy pubkey and login

   1 ssh-copy-id root@steamlink
   2 ssh root@steamlink
   3 X11 forwarding request failed on channel 0
   4 /home/steam
   5 # 
   6

Change password. passwd

You may use busybox as a more comfortable shell to ash.

PS1 is set
Tab completion
…

   1 …
   2 #
   3 # hush
   4 ~ # 
   5 ~ # 
   6

Logs can be found at
/mnt/scratch/log.

Configure

Pubkey Auth Fails

Start a second instance of sshd

   1 /usr/sbin/sshd -E /tmp/sshd.log -p 2222

Connect

   1 ssh -p 2222 root@steamlink

Take a look in the log
/tmp/sshd.log

   1 Authentication refused: bad ownership or modes for directory /home/steam^M
   2 Connection closed by 192.168.182.16 [preauth]^M

It fails because of the ownership of the home directory.

Fix permissions

   1 chmod g-w /home/steam

xow is already running

/mnt/scratch/log/S99steam spams

2020-12-20 22:53:18 ERROR - Another instance of xow is already running                                           
2020-12-20 22:53:18 INFO  - xow v0.5-2-g73f5273 ..Severin v. W.                                                            
2020-12-20 22:53:18 ERROR - Another instance of xow is already running                                                      
2020-12-20 22:53:18 INFO  - xow v0.5-2-g73f5273 ..Severin v. W.                                                  
2020-12-20 22:53:18 ERROR - Another instance of xow is already running                                                     
2020-12-20 22:53:18 INFO  - xow v0.5-2-g73f5273 ..Severin v. W.                                                             
2020-12-20 22:53:18 ERROR - Another instance of xow is already running                                           
2020-12-20 22:53:18 INFO  - xow v0.5-2-g73f5273 ..Severin v. W.                                                            
2020-12-20 22:53:18 ERROR - Another instance of xow is already running                                                      
2020-12-20 22:53:18 INFO  - xow v0.5-2-g73f5273 ..Severin v. W.                                                  
2020-12-20 22:53:18 ERROR - Another instance of xow is already running                                                     
2020-12-20 22:53:18 INFO  - xow v0.5-2-g73f5273 ..Severin v. W.

Alright let's trace it down.

At the end of boot init starts
/etc/init.d/startup/S99steam

   1 #!/bin/sh
   2 
   3 # Start up the streaming UI
   4 /home/steam/rc.local

Which starts /home/steam/rc.local

   1 #!/bin/sh
   2 
   3 cd /home/steam
   4 
   5 export PATH=$PWD/bin:$PATH
   6 export LD_LIBRARY_PATH=$PWD/lib
   7 
   8 export LIBASOUND_THREAD_SAFE=0
   9 export SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt
  10 
  11 # Load modules
  12 KERNEL_RELEASE=$(uname -r)
  13 # Allow custom input drivers
  14 for file in /lib/modules/${KERNEL_RELEASE}/kernel/drivers/hid/* /lib/modules/${KERNEL_RELEASE}/kernel/drivers/input/joystick/*; do
  15     module=$(basename $file)
  16     if [ -f modules/$module.disabled ]; then
  17         continue
  18     fi
  19     if [ -f modules/$module ]; then
  20         file=modules/$module
  21     fi
  22     insmod $file
  23 done
  24 insmod /lib/modules/${KERNEL_RELEASE}/kernel/arch/arm/mach-berlin/modules/pe/galois_pe.ko
  25 insmod /lib/modules/${KERNEL_RELEASE}/kernel/arch/arm/mach-berlin/modules/gpu/gfx.ko
  26 insmod /lib/modules/${KERNEL_RELEASE}/kernel/arch/arm/mach-berlin/modules/gpu3D/gal3d.ko contiguousSize=0x100000
  27 ./bin/xow.sh &
  28 sleep 1
  29 ln -s /dev/graphics/gal3d /dev/gal3d
  30 ln -s /dev/graphics/galcore /dev/galcore
  31 chmod 777 /dev/galcore
  32 
  33 # Note: setting this environment variable is done to prevent having
  34 # PE_Single_CPU come up with one resolution, only to have the shell
  35 # launch and immediately switch resolutions.
  36 RESOLUTION_OVERRIDE_FILE=/mnt/config/system/display_resolution.txt
  37 if [ -f "${RESOLUTION_OVERRIDE_FILE}" ]; then
  38     export PE_USER_DEFAULT_RESOLUTION=$(cat "${RESOLUTION_OVERRIDE_FILE}")
  39 fi
  40 
  41 # Start PE
  42 ./bin/PE_Single_CPU >/mnt/scratch/log/PE_server.log 2>&1 &
  43 
  44 # Enable core dumps and set core dump output path
  45 CORE_PATH=/mnt/scratch/tmp
  46 mkdir -p $CORE_PATH
  47 echo "$CORE_PATH/core.%e" >/proc/sys/kernel/core_pattern
  48 ulimit -c unlimited
  49 
  50 # Start power manager, which will start the application if appropriate
  51 ./bin/powermanager.sh &

/home/steam/bin/xow.sh

   1 #!/bin/sh
   2 
   3 while true; do
   4     xow
   5 done

And this is how XBOX controller driver is started? Honestly … this burns CPU.

Backup old file

   1 cp -p $HOME/bin/xow.sh $HOME/bin/xow.sh_org

A very simple fix would be
/home/steam/bin/xow.sh

   1 #!/bin/sh
   2 
   3 while sleep 0.2; do
   4     pgrep xow > /dev/null || xow
   5 done

There are several instances of xow.sh running on the steamlink.

   1 # ps faux| grep -e xow -e sleep 
   2   424 root       0:00 xow
   3   789 root       0:20 {xow.sh} /bin/sh /home/steam/bin/xow.sh
   4   859 root       0:25 {xow.sh} /bin/sh /home/steam/bin/xow.sh
   5   884 root       0:24 {xow.sh} /bin/sh /home/steam/bin/xow.sh
   6  1167 root       0:23 {xow.sh} /bin/sh /home/steam/bin/xow.sh
   7  1231 root       0:22 {xow.sh} /bin/sh /home/steam/bin/xow.sh
   8  1493 root       0:23 {xow.sh} /bin/sh ./bin/xow.sh
   9  1576 root       0:22 {xow.sh} /bin/sh /home/steam/bin/xow.sh
  10  1661 root       0:37 {xow.sh} /bin/sh /home/steam/bin/xow.sh
  11  1871 root       0:32 {xow.sh} /bin/sh /home/steam/bin/xow.sh
  12  1893 root       0:33 {xow.sh} /bin/sh /home/steam/bin/xow.sh
  13  2657 root       0:43 {xow.sh} /bin/sh /home/steam/bin/xow.sh
  14  2758 root       0:00 sleep 1
  15  2760 root       0:00 sleep 1
  16  2762 root       0:00 sleep 1
  17  2764 root       0:00 sleep 1
  18  2766 root       0:00 sleep 1
  19  2768 root       0:13 {xow.sh} /bin/sh /home/steam/bin/xow.sh
  20  2769 root       0:00 sleep 1
  21  2771 root       0:00 grep -e xow -e sleep
  22  2772 root       0:00 pgrep xow
  23  2773 root       0:00 pgrep xow
  24  2805 root       0:12 {xow.sh} /bin/sh /home/steam/bin/xow.sh
  25  3769 root       0:16 {xow.sh} /bin/sh /home/steam/bin/xow.sh
  26  3802 root       0:15 {xow.sh} /bin/sh /home/steam/bin/xow.sh

So i decided to write a new version with a lock file to avoid duplicate starts of the script.
/home/steam/bin/xow.sh

   1 #!/bin/sh
   2 
   3 LOCK="/var/run/xow.lock"
   4 exec 4<>"$LOCK"
   5 flock -n 4 || exit 2
   6 
   7 while sleep 1; do
   8     pgrep xow > /dev/null || xow
   9 done

Reboot and test

   1 shutdown -r now

OKAY - problem gone.

This saves CPU, thermal capacity and energy.

Crackling sound

When you are streaming from Linux and it's kinda likely that your sound is distorted heavily after some time in game. While stopping and reconnecting the steamlink to the host, this gets annoying very quickly.

There is already an active thread on
Github ValveSoftware/steam-for-linux issues - Remote Play Crackling Audio #6749

Reducing the sampling rate to 44,1 kHz (CD-quality) prolongs the time until the crackling occurs in
/etc/pulse/daemon.conf

   1 default-sample-rate = 44100

It seams that recording the steam audio source froma HDMI port also works around the issue.

Open pavucontrol
Set playback stream of the game to e.g. the HDMI port of your grafics card
Set the recording of steam to the same HDMI device.
Eventually reconnect to the host a last time.

Your problem should be gone.

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