[meta-intel] Atom E3845: Kernel build issues

[Saul Wold]

On 09/22/2015 07:15 AM, Prasant J wrote:
> On Tue, Sep 22, 2015 at 12:18 PM, Prasant J <pj0585 at gmail.com> wrote:
>
>>
>>
>> On Tue, Sep 22, 2015 at 4:51 AM, Saul Wold <sgw at linux.intel.com> wrote:
>>
>>> On 09/21/2015 06:51 AM, Prasant J wrote:
>>>
>>>> Hi,
>>>>
>>>>
>>>> I'm building yocto distro for my custom hardware based on intel Atom
>>>> E3845.
>>>> Below is my yocto build configuration:
>>>>
>>>> BB_VERSION        = "1.24.0"
>>>> BUILD_SYS         = "i686-linux"
>>>> NATIVELSBSTRING   = "Ubuntu-12.04"
>>>> TARGET_SYS        = "i586-poky-linux"
>>>> MACHINE           = "valleyisland-32"
>>>> DISTRO            = "poky"
>>>> DISTRO_VERSION    = "1.7.1"
>>>> TUNE_FEATURES     = "m32 core2"
>>>> TARGET_FPU        = ""
>>>> meta
>>>> meta-yocto
>>>> meta-yocto-bsp    = "(nobranch):ff482c2522f7092216a4ac7b335393a5294d97d5"
>>>> meta-msc-ldk-core = "v0.4.0:ed047edacf285e711c55ed8389111981abc417c7"
>>>>
>>>> meta-valleyisland = "(nobranch):5af06a8b0dd28498e77581f6bcb7fd6f722b755a"
>>>> meta              = "(nobranch):56c6bebdd19b5b64a2585986299543abf6e6ad48"
>>>>
>>>>
>>>>
>>>> I have changed kernel configuration and successfully built it
>>>> (arch/x86/boot/bzImage), but when I copy the newly built kernel to my
>>>> target hardware I do not see the relevant changes.
>>>> I check my kernel config (zcat /proc/config.gz) and my updated
>>>> configuration is not there.
>>>>
>>>
>>> Pj:
>>>
>>> This is sounding similar to your other issue, where are you copying the
>>> files to exactly, what disk or usb device? Are you using initramfs.
>>>
>>> Your using grub, correct?  Have you changed the default grub.conf from
>>> the build?
>>>
>>
>>
>> I'm using GRUB and you are right, the problem is very similar to my GRUB
>> issue (not yet resolved).
>> I have installed the system on an SD Card and booting from that.
>> Its an installed system and I'm not using initramfs.
>>
>> Why should I change he default grub.conf? (Are you referring to my GRUB
>> issue or do I need to update grub.conf for updating the kernel?
>>
>>
>>>
>>>
>>>>
>>>> After updating the configuration, I can see the relevant files being
>>>> built
>>>> (that confirms my changes were applied) also I can see my updated
>>>> configuration is (kernel_source_code/include/config.gz).
>>>> So why can't I see the new configuration on the target hardware?
>>>>
>>>>
>>>> I also tried building the kernel outside the yocto build system (used the
>>>> SDK to build the kernel). Same observations.
>>>>
>>>> Did you rebuild the image or just the kernel?
>>
>>
>> I just rebuilt the kernel. I used the following commands:
>>      bitbake linux-yocto -c menuconfig
>>      bitbake linux-yocto -c compile
>>
>>
>> I copied the latest kernel build from yocto build:
>> tmp/work/core2-32-intel-common-poky-linux/linux-yocto/3.17.1+git...../linux-core2-32-intel-build/arch/x86/boot/bzImage)
>> and replaced 2 files on the target system:
>> GRUB Partition: /vmlinuz
>> ROOT Partition: /boot/bzImage-3.17.1-yocto-standard
>>
>> I also update the kernel modules on the target system.
>>
>>
>> Anything wrong you observe in the above steps?
>>
>>
>> Saul, thanks again for your response.
>>
>>
>> Regards, Pj
>>
>
> Saul, I found the issue.
> There was an old installation on the eMMC flash (another storage) and the
> BIOS boot preferences had changed, so the GRUB and kernel were used from
> the eMMC instead of SD Card. Back to school for me.
>
> Interestingly the root file system was being used from SD Card and not the
> eMMC (that is what misled me all the time). I have to check why root file
> system from SD Card was used. That may be with my setup.
>
This could be from the grub config file, it will use grub and the kernel 
from the eMMC, but if the root= is set it will use the rootfs from 
/dev/mmcblk* if that's setup in the grub config.  Since you did not tell 
me about the eMMC I could not have guessed it would have booted from there.

Glad you figured it out.

Sau!

> Anyway thanks a ton for your responses!
>
> Regards, Pj
>