Panda How to kernel 3 1 rel

Introduction
Kernel 3.1 has been released, and welcome back git.kernel.org, kernel.org still is not fully functional though.

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 v3.1

rc1
Still had issues with the setting up of the wl12xx:

rc2
-rc2 fixes some of the wl12xx issues, but still requires a patch to function. There is still an unresolved start up issue with wl12xx, in that sometimes it will work, sometimes, not. Same kernel, MLO, & u-boot and userspace.

rc3
-rc3 had no OMAP or Panda changes. However there was a boot issue with Panda as described here: https://lkml.org/lkml/2011/8/25/117

rc4
-rc4 had no OMAP or Panda changes. The issue introduced in -rc3 noted above, was resolved.

Figured out you need to build the wl12xx driver as a module, and modprobe it, the wlan seems to start up fine every time, must be some sort of race when it is compiled into the kernel.

rc6
-rc6 had some OMAP4 related changes, but applying the same patches as -rc4, a working kernel as described below is the result.

rc7
-rc7 had no OMAP or Panda related changes, the same patches that worked for -rc4 still work (some with a bit of an offset).

git.kerenl.org
Came back, mostly, as of 10/3/2011.

rc9
The same patches that worked for -rc4 still work (some with a bit of an offset).

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.

[[Media:0006-omap4-usb-improvement.patch|0006-omap4-usb-improvement.patch]]

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

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

wlan12xx patch
This patch is necessary to resolve the issue noted in 3.0 and 3.1-rc1 above, however the code has moved to twl_common.c and so an new patch is presented here.

[[Media:0001a-omap4-pandaboard-wlan-fix.patch|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
This patch is necessary to make 720p resolution available.

[[Media:0003-omap4-pandaboard-dvi720p.patch|0003-omap4-pandaboard-dvi720p.patch]]

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

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

Then use either of the following configs

make ARCH=arm omap2plus_defconfig or make ARCH=arm panda_dvi_defconfig

Compile as above.

I2C Patch
i2c character device driver

Ever since 2.6.38, the i2c character device driver support from user space has been broken for OMAP44xx. * A fix has been submitted for the linux-omap-2.6 branch, but it may be a while till it gets into an -rcx. See http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap.git;a=commit;h=39fe1a6fafe1e85c183379af9f3ceda7cd24bd65 for the commit. * A quick fix for this issue is available

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

patch -p1 < Omap44xx-i2c-fix.patch

Compile as above.

Building Kernel 3.1
Building 3.1 is basically the same as How to build 2.6.38 kernel, but of course you need the 3.1 sources. The omap2plus_defconfig works.

Building is a bit different 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.

Use [[Media:config.3.1.1|config.3.1.1]] as the .config (this requires you patch the dvi, wlan & i2c as above)

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/3.1-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:

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_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 (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.