Debugging the kernel

[Guest Stadou]

Hi everybody,

I'm trying the do some modifications in the 2.6.29 kernel for the Desire. I already partially unlocked my phone using the unrevoked tool.

After having compiled my kernel, I can create a boot.ini file and flash it to the phone using adb when booting in recovery mode (ClockworkMod Recovery v2.5.0.7).

That works. My problem now is that I'm not able to debug the kernel I'm booting. Is there a way to get at least the printk messages or something else that could help me to debug my kernel ?

Thanks in advance

Jérôme

[Guest frankoid]

That works. My problem now is that I'm not able to debug the kernel I'm booting. Is there a way to get at least the printk messages or something else that could help me to debug my kernel ?

"adb shell dmesg" should let you see printk messaged as long as your kernel doesn't crash before adbd is started. I think you might need to install busybox on your phone to get dmesg. "adb shell cat /proc/last_kmsg" and "adb shell cat /proc/kmsg" may also be useful.

AnyKernel is useful when doing kernel development, it lets you make an update zip with your new kernel without having to unpack/repack boot.img

Edited November 6, 2010 by frankoid

[Guest Stadou]

"adb shell dmesg" should let you see printk messaged as long as your kernel doesn't crash before adbd is started. I think you might need to install busybox on your phone to get dmesg. "adb shell cat /proc/last_kmsg" and "adb shell cat /proc/kmsg" may also be useful.

AnyKernel is useful when doing kernel development, it lets you make an update zip with your new kernel without having to unpack/repack boot.img

Thanks for the link to AnyKernel. For the first part of your answer, my problem is that the adb does not work during the boot time because the server has still not been started on the device. What I want to debug is the early start of the kernel.

[Guest frankoid]

Thanks for the link to AnyKernel. For the first part of your answer, my problem is that the adb does not work during the boot time because the server has still not been started on the device. What I want to debug is the early start of the kernel.

Have you tried looking at /proc/last_kmsg the next time you boot (e.g. in recovery)?