U-boot splash screen dual LVDS Apalis imx8

Technical Support
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1

Hi,

we have configured a splash screen for u-boot on Apalis imx8 following the guide (Splash Screen on U-Boot | Toradex Developer Center) but no image is displayed.
Our panel uses dual lvds with DE mode. How can we set mode and timings for our panel in u-boot?

Thank you in advance,
Florian

2

Hi @floji,

Can you confirm that you use a single panel in dual channel mode?

For more information about display timings, Toradex has an article about it. Feel free to give that one a read.

Best Regards
Kevin

3

Hi @kevin.tx ,

yes, we are using an AUO G215HAN01.2 which uses a dual channel interface.
The panel works well with Linux. We just want to add an splash screen with u-boot.

Best Regards,
Florian

4

Hi @floji !

Isn’t suitable for you the splash method that Kevin shared?

If not, could you explain your use case?

Also, maybe this question might be useful for you:

Best regards,

5

Hi @henrique.tx ,

it takes a few seconds till the Linux splash screen is displayed. We would like to avoid the black screen after switching on the device before Linux takes over.

For i.mx8 there is no display_info_t in u-boot’s apalis-imx8.c or can I set the values via u-boot environment?

Best regards,
Florian

6

Hi @floji ,

Alright, could you then please send a log of u-boot after booting?

So we can have a look at some messages there.

Best Regards
Kevin

7

Hi @ floji
I’m curious about your progress ,
I have a similar ( a bit ) system and a similar problem (colibri imx8x+ lvds)
I have the impression that the information on the toradex site is for old systems
, the descriptions do not work on imx8x (in my opinion)

When I see on TORADEX youtuber channel u-boot logo on colibri IMX8X , I will believe it !
I see some people asking about it, but I don’t see any solutions

8

Hi @MariusM

no progress so far.
I think u-boot splash screen is not implemented for mx8 at the moment.

@kevin.tx : I have attached the u-boot log.
u-boot.txt (1.9 KB)

9

Hi @floji

Turns out that U-boot splash screen is not supported for iMX8 based modules.

The Splash Screen on U-Boot | Toradex Developer Center article is not applicable for any iMX8 based modules (we are going to remove them from the “applicable for” at the top).

Regarding boot time optimization, we have these resources:

Best regards

10

Hi @henrique.tx ,

since splash screen support for kernel has been dropped with BSP 6 we are now running out of options. Running a user space splash application takes way too long.
Is there any chance we might get U-Boot splash support on iMX8 or at least get the kernel splash screen back? Other SOM manufacturers do support splash screens for U-Boot and kernel.

Regards

11

Hi @floji !

We have some resources that might help you to optimize the boot speed of your OS:

I will bring up your request internally.

Best regards,

12

Hi @floji !

By the way, could you please specify what is your time requirement regarding the Splash Screen logo?

Best regards,

13

Hi @henrique.tx ,

the earlier a splash screen is shown the better. I think 1.5 (2s max) would be good. Customers start to get nervous if a blank screen is shown longer.
Our current unit (iMX6) shows boot loader splash screen almost instantly and then blends over to kernel splash screen. Loading our application takes a few seconds so early feedback is required.

Best regards,

14

Hi @floji !

And how long is taking currently for your splash screen to be displayed?

Did you try to use the tools/methods from the links shared previously to optimize your boot time?

Best regards,

15

Hi @henrique.tx ,

sorry for the late reply.
I’ve installed psplash using initramfs. Currently it takes around 6,5s for the splash screen to appear.
I tried all the “low-hanging fruit” from the links you provided. There are a few things left that I can do (e.g. further reducing kernel size) but I doubt that I can save more than additional 0,5-1,0s.

Best regards,
floji

16

Hi @floji!

Thanks for the reply.

Could you please tell us more about this? Which exact strategy was used here? Also, if possible share the version of software used (e.g. kernel - upstream or downstream? -, u-boot, psplash). Also, how the handover was implemented?

If you prefer, we can make this thread non-public, so you can share more details.

Best regards,

17

Hi @henrique.tx ,

our iMX6 based product uses Windows EC7 not Linux. I just mentioned it for reference.

Best regards,

18

Hi @floji !

Sorry for the long delay.

I was informed you were in touch via email with the Toradex team and got the recent update related to this thread.

For completeness, I will add it here in the Community as well.

The current state of Splash Screen:

  • Different modules have different requirements/limitations, and no one-size-fits-all solution;
    • Not to mention that Toradex is concerned about supporting several different display interfaces and each of them would need some kind of tweaking.
  • Mainline U-boot doesn’t support video displays on i.MX8-based modules. It’s not clear if it’s supported downstream;
  • U-boot Splash Screen is very static and requires U-boot recompilation;
  • Linux Kernel Splash Screen is also very limited, static, and requires Kernel recompilation;
  • There seems to be no mechanism for a smooth transition of the video handling between U-boot and the Linux Kernel.

The discussion about what is going to be done and research about the topic is still ongoing. I can say that we are at least going to have some documentation showing methods for enabling it.

Best regards,

19

Hi @henrique.tx ,

is there any news on that topic?

Best regards,

20

Hi @floji!

The discussion/investigation is still ongoing.

Best regards,