imx6qdl based board won't boot with kernel 4.9.x

imx6qdl based board won't boot with kernel 4.9.x

[Cory]

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Hi all,

I've been battling with upgrading the kernel our imx6qdl based custom board using Yocto Thud. We have been happily running the linux-imx 4.1-2 kernel, but it's time to push it forward to the 4.9.x versions. But it's not booting, at all. I've be poring over changes to other imxqdl based device trees and defconfigs, and nothing is making sense as to what change I may have missed (because I can't find many). We are running U-Boot 2017.11 (I know that could also be upgraded, but that shouldn't matter...unless I'm wrong).

I've stripped our kernel customizations down to nothing except for our board device tree, which works fine in kernel 4.1-X. We've never had issues like this with a kernel version bump before. After U-Boot loads the device tree and kernel, there is no output. When I check the HW, I've probed the DDR clock and it's stuck high. All 4.9+ kernels included in meta-freescale behave this same way:

## Booting kernel from Legacy Image at 10800000 ...

Image Name:   Linux-4.9.123-imx+g6a71cbc

Image Type:   ARM Linux Kernel Image (uncompressed)

Data Size:    5476256 Bytes = 5.2 MiB

Load Address: 10808000

Entry Point:  10808000

Verifying Checksum ... OK

## Flattened Device Tree blob at 11000000

Booting using the fdt blob at 0x11000000

Loading Kernel Image ... OK

Using Device Tree in place at 11000000, end 1100dd66

Starting kernel ...

## NOTHING AFTER THIS ##

My main question is, has anyone else successfully used the linux-imx 4.9.x kernels (4.9.11, 4.9.123, etc), on a board based on the imx6qdl, and if so, do you have any tricks I'm missing? Has something major changed  in 4.9.x that affects the imx6 that I may have missed? (except for the framebuffer, that's another issue I'll deal with later).

I appreciate any guidance!

Cheers,
Cory

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Re: [meta-freescale] imx6qdl based board won't boot with kernel 4.9.x

[Marc Ferland]

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On Wed, Dec 11, 2019 at 9:10 AM Cory <cory@otis8.com> wrote:

> Hi all,
>
> I've been battling with upgrading the kernel our imx6qdl based custom
> board using Yocto Thud. We have been happily running the linux-imx 4.1-2
> kernel, but it's time to push it forward to the 4.9.x versions. But it's
> not booting, at all. I've be poring over changes to other imxqdl based
> device trees and defconfigs, and nothing is making sense as to what change
> I may have missed (because I can't find many). We are running U-Boot
> 2017.11 (I know that could also be upgraded, but that shouldn't
> matter...unless I'm wrong).
>
> I've stripped our kernel customizations down to nothing except for our
> board device tree, which works fine in kernel 4.1-X. We've never had issues
> like this with a kernel version bump before. After U-Boot loads the device
> tree and kernel, there is no output. When I check the HW, I've probed the
> DDR clock and it's stuck high. All 4.9+ kernels included in meta-freescale
> behave this same way:
>
> ## Booting kernel from Legacy Image at 10800000 ...
>
>    Image Name:   Linux-4.9.123-imx+g6a71cbc
>
>    Image Type:   ARM Linux Kernel Image (uncompressed)
>
>    Data Size:    5476256 Bytes = 5.2 MiB
>
>    Load Address: 10808000
>
>    Entry Point:  10808000
>
>    Verifying Checksum ... OK
>
> ## Flattened Device Tree blob at 11000000
>
>    Booting using the fdt blob at 0x11000000
>
>    Loading Kernel Image ... OK
>
>    Using Device Tree in place at 11000000, end 1100dd66
>
> Starting kernel ...
>
> ## NOTHING AFTER THIS ##
>
> My main question is, has anyone else successfully used the linux-imx 4.9.x
> kernels (4.9.11, 4.9.123, etc), on a board based on the imx6qdl, and if so,
> do you have any tricks I'm missing? Has something major changed  in 4.9.x
> that affects the imx6 that I may have missed? (except for the framebuffer,
> that's another issue I'll deal with later).
>
> Happens to me from time to time. Generally it is something with the kernel
configuration (try deactivating stuff in the kernel until you get something
that boots) or the device tree (again try commenting stuff out until you
see a change, I've seen DTBs working with old kernel and breaking with
recent ones).

Hope that helps,

Marc

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Re: [meta-freescale] imx6qdl based board won't boot with kernel 4.9.x

[Richard Leitner]

Hi,

some things I would try/check:

  * is the kernel not booting or just failing to output to the serial?
    to check this you may for example add a heartbeat LED...
  * enable debug-ll, earlyprintk and similar stuff and see if you get
    more output
  * use a real debugger (if you have one)

hope that helps.

regards;richard.l

On 11/12/2019 16:05, Marc Ferland wrote:
> On Wed, Dec 11, 2019 at 9:10 AM Cory <cory@otis8.com 
> <mailto:cory@otis8.com>> wrote:
> 
>     Hi all,
> 
>     I've been battling with upgrading the kernel our imx6qdl based
>     custom board using Yocto Thud. We have been happily running the
>     linux-imx 4.1-2 kernel, but it's time to push it forward to the
>     4.9.x versions. But it's not booting, at all. I've be poring over
>     changes to other imxqdl based device trees and defconfigs, and
>     nothing is making sense as to what change I may have missed (because
>     I can't find many). We are running U-Boot 2017.11 (I know that could
>     also be upgraded, but that shouldn't matter...unless I'm wrong).
> 
>     I've stripped our kernel customizations down to nothing except for
>     our board device tree, which works fine in kernel 4.1-X. We've never
>     had issues like this with a kernel version bump before. After U-Boot
>     loads the device tree and kernel, there is no output. When I check
>     the HW, I've probed the DDR clock and it's stuck high. All 4.9+
>     kernels included in meta-freescale behave this same way:
> 
>     ## Booting kernel from Legacy Image at 10800000 ...
> 
>         Image Name:   Linux-4.9.123-imx+g6a71cbc
> 
>         Image Type:   ARM Linux Kernel Image (uncompressed)
> 
>         Data Size:    5476256 Bytes = 5.2 MiB
> 
>         Load Address: 10808000
> 
>         Entry Point:  10808000
> 
>         Verifying Checksum ... OK
> 
>     ## Flattened Device Tree blob at 11000000
> 
>         Booting using the fdt blob at 0x11000000
> 
>         Loading Kernel Image ... OK
> 
>         Using Device Tree in place at 11000000, end 1100dd66
> 
>     Starting kernel ...
> 
>     ## NOTHING AFTER THIS ##
> 
>     My main question is, has anyone else successfully used the linux-imx
>     4.9.x kernels (4.9.11, 4.9.123, etc), on a board based on the
>     imx6qdl, and if so, do you have any tricks I'm missing? Has
>     something major changed  in 4.9.x that affects the imx6 that I may
>     have missed? (except for the framebuffer, that's another issue I'll
>     deal with later).
> 
> Happens to me from time to time. Generally it is something with the 
> kernel configuration (try deactivating stuff in the kernel until you get 
> something that boots) or the device tree (again try commenting stuff out 
> until you see a change, I've seen DTBs working with old kernel and 
> breaking with recent ones).
> 
> Hope that helps,
> 
> Marc
> 
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> 
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> Unsubscribe: https://lists.yoctoproject.org/g/meta-freescale/unsub  [richard.leitner@skidata.com]
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> 

Re: imx6qdl based board won't boot with kernel 4.9.x

[Cory]

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Hi Marc,

Many thanks for the reply, that's exactly what I've been doing for a while now, no luck yet. I've gone as far as using a very generic IMX defconfig and device tree with almost none of our in-house required changes. But, I'll keep at it as well.

Cheers,
Cory

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Re: imx6qdl based board won't boot with kernel 4.9.x

[Cory]

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Hi Richard,

It's definitely not a serial issue (I checked that first). I've gone as far as probing the DDR clock line with a logic analyzer...and it it comes to sudden halt as soon as the 4.9+ kernels are loaded by U-Boot.

I don't have access to an ICE at the moment for any hardcore debugging, but I have a logic analyzer, so I'm checking heartbeats with that at the moment.

I'll check earlyprintk, just in case.

Thanks for the reply,
Cory

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Re: imx6qdl based board won't boot with kernel 4.9.x

[Cory]

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Hi Stefan,

I've been also looking at moving to linux-fslc, but we are dependent on the vivante GPU, so I am somewhat limited.

I've also completely removed our display subsystem configuration in the device tree, just in case, just to try and get things booting.

Thanks for the information, it's good to know.

Cheers,
Cory

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Re: imx6qdl based board won't boot with kernel 4.9.x

[Cory]

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Hi Stefan,

Thanks for the response. However, I don't think it's an issue with the the LOADADDR. See below, the same board booting with the "old" 4.1.15 kernel, same LOADADDR. For reasons a long time ago, that's what we've used for years as the LOADADDR.

Are you using the i.MX6DL with one of the 4.9.x kernels? If so, did you have to do anything special that you remember?

Successful 4.1.15 kernel boot:

## Booting kernel from Legacy Image at 10800000 ...
Image Name:   Linux-4.1.15-2.1.0+g30278ab
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    5151184 Bytes = 4.9 MiB
Load Address: 10808000
Entry Point:  10808000
Verifying Checksum ... OK
## Flattened Device Tree blob at 11000000
Booting using the fdt blob at 0x11000000
Loading Kernel Image ... OK
Using Device Tree in place at 11000000, end 1100d4f1

Starting kernel ...

Booting Linux on physical CPU 0x0
Linux version 4.1.15-2.1.0+g30278ab (oe-user@oe-host) (gcc version 7.3.0 (GCC) ) #7 SMP PREEMPT

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