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FAQ OMAP35x Linux PSP

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Introduction

The Linux PSP for OMAP35x is based on the OMAP3EVM. This page lists the FAQs related to the various PSP releases.

This section lists the FAQs that are generic and don't depend upon a specific release version.


How to choose the correct configuration for the processors in the OMAP35x family?

  1. Start with the default configuration for the OMAP3EVM. OMAP3503 is chosen as default processor.
  2. Invoke Linux Kernel Configuration tool
$ make menuconfig
  1. Select the sub-menu: System Type
  2. Select sub-menu: OMAP35x Family > Current Choice (OMAP3503)
  3. Select the available processors in the list (See below)
.config - Linux Kernel v2.6.22.18-omap3 Configuration
-----------------------------------------------------------------------------

   +-------------------------- Current choice --------------------------+
   |  Use the arrow keys to navigate this window or press the hotkey of |
   |  the item you wish to select followed by the <SPACE BAR>. Press    |
   |  <?> for additional information about this option.                 |
   | +----------------------------------------------------------------+ |
   | |                          (X) OMAP3503                          | |
   | |                          ( ) OMAP3530                          | |
   | |                                                                | |
   | |                                                                | |
   | +----------------------------------------------------------------+ |
   +--------------------------------------------------------------------|
   |                       <Select>      < Help >                       |
   +--------------------------------------------------------------------+

How to enable the NEON coprocessor?

  1. Start with the your current configuration for the OMAP3EVM.
  2. Invoke Linux Kernel Configuration tool
  3. Select the sub-menu: Floating point emulation
  4. Enable the Neon coprocessor. (See below).
.config - Linux Kernel v2.6.22.18-omap3 Configuration
-----------------------------------------------------------------------------

  +----------------------- Floating point emulation ------------------------+
  |  Arrow keys navigate the menu.  <Enter> selects submenus --->.          |
  |  Highlighted letters are hotkeys.  Pressing <Y> includes, <N> excludes, |
  |  <M> modularizes features.  Press <Esc><Esc> to exit, <?> for Help, </> |
  |  for Search.  Legend: [*] built-in  [ ] excluded  <M> module  < >       |
  | +---------------------------------------------------------------------+ |
  | |    --- At least one emulation must be selected                      | |
  | |    [*] NWFPE math emulation                                         | |
  | |    [ ]   Support extended precision                                 | |
  | |    [ ] FastFPE math emulation (EXPERIMENTAL)                        | |
  | |    [*] VFP-format floating point maths                              | |
  | |    [*]   NEON Advanced SIMD Extension support                       | |
  | |                                                                     | |
  | |                                                                     | |
  | |                                                                     | |
  | +---------------------------------------------------------------------+ |
  +-------------------------------------------------------------------------|
  |                    <Select>    < Exit >    < Help >                     |
  +-------------------------------------------------------------------------+

Note: If you have chosen OMAP3530 as processor in the configuration, NEON is enabled by default. In this case, the option is not editable.

Unable to mount remote filesystem using NFS

Most of the times we try to mount the remote filesystems using NFS as:

$ mount -t nfs 192.168.1.10:/home/user/share /mnt

On a regular Linux PC this command will succeed. But you are very likely to see this command failing on embedded systems with these errors:

rpcbind: server localhost not responding, timed out
RPC: failed to contact local rpcbind server (errno 5).
rpcbind: server localhost not responding, timed out
RPC: failed to contact local rpcbind server (errno 5).
lockd_up: makesock failed, error=-5
rpcbind: server localhost not responding, timed out
RPC: failed to contact local rpcbind server (errno 5).
mount: mounting 192.168.1.10:/home/user/share on /mnt failed: Input/output error

This means that filesystem used on your hardware is not running rpc.lockd daemon.

In this case use this command to mount remote filesystems:

$ mount -t nfs -o nolock 192.168.1.10:/home/user/share /mnt

See manpage of mount for more details on the option "nolock".

Unable to boot with the NFS filesystem included in the package

Let us assume that NFS package (nfs.tar.gz) was extracted at location /home/user/nfs_share.

  • First ensure that you are able to mount the path /home/user/nfs_share.
  • Change to the directory "/home/user/nfs_share/dev".
  • Check if these files exist in this directory - console, null.

If you are unable to boot, chances are, that these files are not present. This will be the case if you extracted the NFS package as a 'normal' user. Normal users do not have permissions to create device nodes.

Either login as 'root' or get sudo access on the system and

Option 1) Extract the NFS package again.

Option 2) Manually create the device nodes

$ mknod null    c 1 3
$ mknod console c 5 1

Which software component has maximum contribution toward power consumption?

To build power efficient systems, it is necessary to identify the components that are major contributors to the consumed power.

PowerTOP is one such utility. See Running PowerTOP on OMAP35x platform for more details on executing this utility on OMAP35x platforms.

PSP version 0.9.8

This section lists the FAQs specific to the PSP version 0.9.8.


PSP version 1.0.0

This section lists the FAQs specific to the PSP version 1.0.0.

How do I get DVI working?

The OMAP3EVM requires HW modification for DVI to work if using one of the early adopter boards (current production boards have the mod in place). The resistor R18 needs to be replaced with a 510 ohm resistor. (See the User Guide for more details).

Which resolutions are supported for DVI?

  • 480p @ 60fps
  • 720p @ 60fps