Panda How to kernel 3 3 rcx

Introduction
The merge window for 3.3 is over and we are currently at v3.3-rc2. Lots of work on the OMAP platforms and on Pandaboard as well as the wl12xx wlan driver. Let's see what the various release candidates have provided.

You can download a tarball of the mainline kernel at http://kernel.org/

or you can clone a copy of mainline kernel with:

git clone http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git cd linux git checkout v3.3-rcx

where x is the release candidate version.

rc1
The WLAN no longer requires a patch! The WL12xx driver needs current firmware. 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.

rc2
No PandaBoard changes, and with no patches required this is an easy release to build.

PandaBoard ES
There is now a PandaBoard ES http://pandaboard.org/content/pandaboard-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 be specifically crafted for the 4460. The thermal management is not in the mainline 4430 code as yet and therefore the max clock frequency when running the OMAP4460 on the PandaBoard ES with the mainline kernel is 920MHz(same as the OMAP4430).

wlan12xx
The latest wlan firmware is available from git: git://git.kernel.org/pub/scm/linux/kernel/git/dwmw2/linux-firmware.git just copy the contents of the ti-connectivity folder to /lib/firmware/ti-connectivity.

The patch is no longer necessary to resolve the issue noted in 3.0, 3.1 and 3.2. In addition, the race issue that required building as a module has been resolved. As part of the code cleanup, the wl12xx and wl12xx_sdio drivers no longer depend on each other. This creates an issue with systems that do not use udev or mdev (with as somewhat fiddly & slow script) to load MODALIAS drivers. The quick solution is to modprobe both, the order no longer matters. Just modprobing wl12xx_sdio will no longer automatically load wl12xx. For this How To, we will build the drivers into the kernel.

I2C Patch
i2c character device driver patch that has been necessary is no longer required, and the issues from kernel 3.2 have been resolved.

Building
Building 3.3-rc1 or -rc2 is fairly straight forward.

Grab the 3.3-rc1 or 3.3-rc2 sources and use [[Media:config.3.3-rc1.1|config.3.3-rc1.1]] or [[Media:config.3.3-rc2.1|config.3.3-rc2.1]] as the .config

The 3.3-rc1 .config enables Sound builtin and wl12xx as modules and the 3.3-rc2 enables Sound and the wl12xx drivers builtin, so the resulting kernel will be a bit bigger than previously.

Then compile like so:

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

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:

echo "1" > /sys/devices/platform/omapdss/display1/enabled echo "0" > /sys/devices/platform/omapdss/overlay0/enabled echo "tv" > /sys/devices/platform/omapdss/overlay0/manager echo "1" > /sys/devices/platform/omapdss/overlay0/enabled
 * 1) Enable HDMI
 * 1) Disable overlay0 (an overlay must be disabled before changing its properties)
 * 1) Set the manager of overlay0 to display1 which is HDMI
 * 1) Enable overlay0

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: http://omappedia.org/wiki/Bootargs_for_enabling_display 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:

echo "0" > /sys/devices/platform/omapdss/display1/enabled echo "0" > /sys/devices/platform/omapdss/overlay0/enabled echo "lcd2" > /sys/devices/platform/omapdss/overlay0/manager echo "1" > /sys/devices/platform/omapdss/overlay0/enabled
 * 1) Disable HDMI
 * 1) Disable overlay0 (an overlay must be disabled before changing its properties)
 * 1) Set the manager of overlay0 to display0 which is DVI
 * 1) Enable overlay0

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.



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

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: -- -- -- -- -- -- -- --
 * 1) i2cdetect -y -r 1

wlan
Run the following commands after the PandaBoard is booted:

modprobe wl12xx   ** only if you built the wl12xx drivers as modules modprobe wl12xx_sdio   ** only if you built the wl12xx drivers as module 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 www.google.com (74.125.73.99): 56 data bytes 64 bytes from 74.125.73.99: seq=0 ttl=43 time=62.683 ms 64 bytes from 74.125.73.99: seq=1 ttl=43 time=54.077 ms 64 bytes from 74.125.73.99: seq=2 ttl=43 time=51.484 ms 64 bytes from 74.125.73.99: seq=3 ttl=43 time=54.108 ms
 * 1) ping www.google.com

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.