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Panda How to kernel 3 2 rcx

Revision as of 16:50, 24 November 2011 by KenMcGuire (Talk | contribs)

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The merge window for 3.2 is over and the 3.2-rc1 kernel has been released. Lots of work on the omap platforms and on pandaboard. Let's see what -rc1 has brought.


There are several issues requiring new patches. The WL12xx driver needs newer firmware, and the same patch as used for 3.1. when the driver isn't happy, the error messages are somewhat less than useful, however the drivers/firmware are being constantly improved and it would not be a good idea to have the driver support anything but the latest firmware. Still a work in progress.


There are no changes to OMAP or PandaBoard related code in the -rc2 release, or any fixes that would eliminate any of the patches required for -rc1, so we'll skip testing this release for a bit.


There were no changes to OMAP or PandBoard related code in the -rc3 release. The same patches required for -rc1 work for the -rc3 sources, and the kernel works as does the -rc1.

More as the -rcx series evolves.


There is now a PandaBoare-ES which includes an OMAP 4460 at up to 1.2GHz. Several important differences make it important (at the present time) that the MLO/u-boot/kernel be specifically crafted for the 4460. The thermal management is not in the mainline 4430 code as yet and could cause unwanted thermal problems. So BEWARE of running any code built for the non -ES PandaBoard on the -ES model.

The latest wlan firmware is available from git: git:// just copy the contents of the ti-connectivity folder to /lib/firmware/ti-connectivity.

wlan12xx patch

This patch is necessary to resolve the issue noted in 3.0 and 3.1, the code was moved to twl_common.c and a patch is supposed to be in -rc2 or -rc3.


Apply it like so: (from inside the kernel sources directory)

patch -p1 < 0001a-omap4-pandaboard-wlan-fix.patch

DVI Patch

This patch is necessary to make 720p resolution available. there is also a new selection in the .config file for DVI


Apply it like so: (from inside the kernel sources directory)

patch -p1 < 0001-omap4-pandaboard-dvi720p.patch

I2C Patch

i2c character device driver patch that has been necessary is no longer required, however a couple of issues still need patching, so a new patch is required


Apply it like so: (from inside the kernel sources directory)

patch -p1 < 0002a-omap4-pandaboard-i2c.patch

USB Performance improvement

This patch fixs one performance bug on ARM Cortex A9 dual core platform, which has been reported on quite a few ARM machines (OMAP4, Tegra 2, snowball...), see details from link of


Apply it like so: (from inside the kernel sources directory)

patch -p1 < 0006-omap4-usb-improvement.patch


Building 3.2-rc1,3 is a bit different from previous How-To's if you want to have a working wlan.

In order to ensure that the wlan starts up consistently, it is recommended that the wl12xx driver be built as a module and started after the PandaBoard has booted.

Grab the 3.2-rc1,3 sources and use config.3.2-rc1.1 or config.3.2-rc3.1 as the .config (you should apply all the above patches)

Then compile like so:

make ARCH=arm CROSS_COMPILE=Path_to_your/arm-2010q1/bin/arm-none-linux-gnueabi- uImage

Then compile the modules like so:

make ARCH=arm CROSS_COMPILE=/home/kenm/Panda/arm-2010q1/bin/arm-none-linux-gnueabi- modules

"Install" the modules to somewhere convenient:

make ARCH=arm CROSS_COMPILE=/home/kenm/Panda/arm-2010q1/bin/arm-none-linux-gnueabi- INSTALL_MOD_PATH=../testlib_omap modules_install 

Copy lib/modules/3.2.0-rc1-dirty/ to your SD card (as root), boot up the Pandaboard.


fbtest on DVI Port

After booting run fbtest to see a nice test pattern from the dvi port.


Switching primary display to the HDMI port

Make sure that a monitor is plugged into the HDMI port before doing the following:

# Enable HDMI
echo "1" > /sys/devices/platform/omapdss/display1/enabled

# Disable overlay0 (an overlay must be disabled before changing its properties)
echo "0" > /sys/devices/platform/omapdss/overlay0/enabled

# Set the manager of overlay0 to display1 which is HDMI
echo "tv" > /sys/devices/platform/omapdss/overlay0/manager

# Enable overlay0
echo "1" > /sys/devices/platform/omapdss/overlay0/enabled

And content on overlay 0 of primary lcd would be transferred to HDMI. It works similarly for all other overlay's.

Switching primary display to the DVI port

See: for lots of useful info on the display subsystem. Be aware that the display, manager and overlay numbers don't match the panda configuration.

Make sure that a monitor is plugged into the DVI port before doing the following:

# Disable HDMI
echo "0" > /sys/devices/platform/omapdss/display1/enabled

# Disable overlay0 (an overlay must be disabled before changing its properties)
echo "0" > /sys/devices/platform/omapdss/overlay0/enabled

# Set the manager of overlay0 to display0 which is DVI
echo "lcd2" > /sys/devices/platform/omapdss/overlay0/manager

# Enable overlay0
echo "1" > /sys/devices/platform/omapdss/overlay0/enabled

The above commands should be run from the serial console and the cable should be in the destination port before running the commands.

fbtest on HDMI Port

Run fbtest to see a nice test pattern from the HDMI port.



You can run i2cdetect and the results should look like this:

# i2cdetect -y -r 1
    0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- UU UU UU UU -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --


Run the following commands after the PandaBoard is booted:

modprobe wl12xx_sdio
ifconfig wlan0 up
iwconfig wlan0 essid "Your AccessPoint Name"
udhcpc -i wlan0

If your network is set up to provide DHCP services, the PandaBoard will get all the "right stuff(tm)" and you will be able to access the Internet.

# ping
PING ( 56 data bytes
64 bytes from seq=0 ttl=43 time=62.683 ms
64 bytes from seq=1 ttl=43 time=54.077 ms
64 bytes from seq=2 ttl=43 time=51.484 ms
64 bytes from seq=3 ttl=43 time=54.108 ms

USB Performance

Insert a USB memory stick into one of the usb ports

Run dmesg to see what sdx the stick was recognised as, then:

hdparam -tT /dev/sdx

If you did this on a kernel without the patch you will see some improvement, if you run the same command on a desktop Linux system, with the same USB memory stick, the PandaBoard's speed should roughly be the same.