NVIDIA Tegra Tegra Linux Driver Package
Developers' Guide

September 4, 2012
R16 Release


FAQs
How do I use a 64-bit Ubuntu host system with NVIDIA® Tegra® Linux Driver Package?
If you are running a 64-bit Ubuntu installation on the host PC, this release requires that you have 32-bit runtime support installed as well. The simple steps for installing 32-bit support on an Ubuntu host use the apt-get command.
To install 32-bit runtime support
$ sudo apt-get update
$ sudo apt-get install ia32-libs
Note: If ia32-libs is not installed, flashing the boot loader with the kernel (and, possibly, other steps in the process) will fail.
How do I use display mode and resolution configuration with the X RandR application?
You can use the X Resize, Rotate and Reflect Extension (RandR) extension to manipulate and configure the attached displays (both the internal panel and any externally connected HDMI® panel). The xrandr(1) utility is the most common way to do this.
A tutorial on xrandr can be found on the following website:
http://www.thinkwiki.org/wiki/Xorg_RandR_1.2
Are there generated ssh host keys for the sample file system?
There are no keys in the /etc/ssh directory of the provided sample file system. For information about creating the ssh host keys, see the ssh-keygen man page. For more information, see the About the Root File System topic in the Getting Started chapter.
How do I determine the X driver ABI of the X server used in the root file system?
All tegra_drv.abi*.so files are in the driver package. By default the apply_binaries.sh script creates a sym-link from tegra_drv.so to the X ABI driver compatible with the provided sample file system. For more information, see the Setting Up the Root File System topic in the Getting Started chapter.
How do I install Ubuntu Desktop?
The default sample file-system that is provided with the release was created with minimal packages pre-installed. For more information on which packages are present, see the Setting Up Your File System topic in the Getting Started chapter.
Please note the possible space constraints with the default partition size specified in the flash.sh that is referenced in this document. To increase the partition size so that it can accommodate additional packages, see the Increasing the Internal Memory Partition Size for the Root File System topic in the Getting Started chapter.
To install the full Ubuntu desktop
1.
First follow the instructions from the Installing Additional Packages topic in the Getting Started chapter.
2.
$ sudo apt-get install ubuntu-desktop
Note: For the default username and password, see the About the Root File System topic in the Getting Started chapter.
Can I install a different X driver Application Binary Interface (ABI)?
Yes. For more information, see the Setting Up the Root File System topic in the Getting Started chapter.
How do I disable the Ubuntu firewall which can block NFS root access?
See the Configuring NFS Root on the Linux Host topic in the Getting Started chapter.
What is the sample rootfs log-in password?
The username is ubuntu and the password ubuntu. For more information about the sample file system, see the Setting Up Your File System topic in the Getting Started chapter.
How do I prevent the system display from blanking out?
Linux kernel 3.1 (and later) adds a power saving feature that may blank the display of an idle system even when applications are running. The feature is called console blank (screen saver). It is defined as:
consoleblank= [KNL]
Where [KNL] is the console blank (screen saver) timeout in seconds. This defaults to 10*60 = 10 mins. A value of 0 disables the blank timer.
By passing arguments to the kernel command line, you can:
Set the timeout to a longer interval.
With the flash.sh script, you can override the kernel command line options passed from fastboot to the kernel. For more information, see the Flash Script Usage topic in the Getting Started chapter.
To disable the console blank (screen saver) from the kernel command line
1.
Add the following line to the kernel parameters in the grub configuration:
consoleblank=0
2.
View the current consoleblank value with the following command:
$ cat /sys/module/kernel/parameters/consoleblank
To disable the console blank feature with an escape sequence
$ echo -ne "\033[9;0]"
To change the console blank timeout value with an escape sequence
$ echo -ne "\033[9;<timeout>]"
where <timeout> is the timeout in seconds.
For more information on this escape sequence, see the console_codes(4) man page documents. For information on the input/output controls that provide some of the same functionality, see the console_ioctl(4) man page.
What is ‘softfp’ (also known as armel)?
Softfp means “software floating point”. Softfp systems perform floating point instructions with software floating point instructions instead of with the full capabilities of the Floating Point Unit (FPU).
What is ‘hardfp’ (also known as armhf)?
Hardfp means “hardware floating point”. Hardfp systems execute floating point instructions with full hardware floating-point support.
Are softfp binaries compatible with a hardfp distro? Are hardfp binaries compatible with a softfp distro?
No. Softfp binaries can only be used in a full softfp distro, and hardfp binaries can only be used in a full hardfp distro.
How do I prevent the file system from becoming read-only on resume if an SD card is in the Card Reader?
If the device resumes from Suspend (LP1) while an SD card is in a connected card reader device, the file system is mounted as read-only resulting in a card reader read/write error and a system reboot is required. The workaround is to install the udisks utility (The usdisks utility has a Debian package name similar to udisks_1.0.2-4ubuntu_armel.deb for the appropriate Ubuntu distro and softfp build. Hardfp packages are often labeled “armhf”).
Can I use an SD card with a card reader already connected to the device?
If the user connects the card reader to the device before inserting the SD card into the card reader, the SD card is not detected. The SD card and card reader must be connected to the device simultaneously. The workaround is to install the udisks utility (The usdisks utility has a Debian package name similar to udisks_1.0.2-4ubuntu_armel.deb Hardfp packages are often labeled “armhf”).