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Panda How to kernel 3 2 rel

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Revision as of 21:01, 5 January 2012 by KenMcGuire (Talk | contribs)

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Introduction

Kernel 3.2 has been released. kernel.org still is not fully functional though, as trying to view patches or vies inc, results in:

diffview is looping on the cached resource:
/home/httpd/cache/diffview/J9/J9_s6TDV1mBJyMRE8KOskHYftVY/index


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 v3.2

Highlites of the -rc series

rc1

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.

rc2

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.

rc3

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

rc4

There were quite a few updates to OMAP code, but no PandaBoard related changes. The same patches required for -rc1 & -rc3 work for the -rc4 sources, and the kernel worked as does the -rc1 & -rc3.

rc5

There were no changes to OMAP or PandaBoard related code in the -rc5 release. The same patches required for -rc1, -rc3 & -rc4 work for the -rc5 sources, and the kernel worked as well.

rc6

There were no changes to PandaBoard related code in the -rc6 release. The same patches required for -rc1, -rc3, -rc4 & -rc5 work for the -rc6 sources, and the kernel worked as well.

rc7

There were no changes to PandaBoard related code in the -rc7 release, although there was an OMAP change relating to I2c. The same patches required for -rc1, -rc3, -rc4, -rc5 and -rc6 work for the -rc7 sources, and the kernel worked.

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).


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.

wlan12xx patch

This patch is still necessary to resolve the issue noted in 3.0 and 3.1, the code was moved to twl_common.c.

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

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

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

DVI Patch

A patch is no longer necessary to make 720p resolution available. The DVI driver now reads the EDID and sets the resolution on bootup if the display is plugged into the DVI connector. If the display is not plugged in on bootup it will default to 640 x 480.

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

0002a-omap4-pandaboard-i2c.patch

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 https://bugs.launchpad.net/bugs/709245.

0006-omap4-usb-improvement.patch

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

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

Building

Building 3.2 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 sources and use config.3.2.1, 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-dirty/ to your SD card (as root), boot up the Pandaboard. The modules are located in lib/modules/3.2.0-dirty/

Testing

fbtest on DVI Port

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

Fbtest.jpg

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: 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:

# 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.

Fbtest2.jpg

i2cdetect

Unfortunately there was an issue introduced between 3.2-rc7 and 3.2 that results in an I2C timeout when the bus is queried.

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:          -- [   19.281738] omap_i2c omap_i2c.1: controller timed out
-- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- UU UU UU UU -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --  

wlan

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 www.google.com
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

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.