STM32F769 - Deep sleep + LCD - DSI / Screen not working on wake up

[ladislas]

Description of defect

Hi there!

Our product using and STM32F769 + OTM8009A LCD screen (the same as the DISCO_F769) has been working great for quite some time now. We've been using all the drivers provided by ST to have the LCD run and display images or play videos.

Recently, we have been working on enabling deep sleep in our product to reduce power consumption when it's not used.

We've discovered that when exiting deep sleep the screen start behaving strangely until it completely stops working.

It looks like this:

Colors are shifting when we turn off (deep sleep) and turn on (wake up) the video. Position is also shifting. If you do that in a loop, sometimes it "works again" then fails again until it eventually crashes completely.

The PR adding the bug is here:

https://github.com/leka/LekaOS/pull/1173/files

Our guess is that there are issues with the DSI or LTDC clock when deep sleeping / waking up, but we don't even know where to start looking...

Any ideas @jeromecoutant? :slight_smile:

Thanks for the help!

Best,
-- Ladislas

Target(s) affected by this defect ?

STM32F769

Toolchain(s) (name and version) displaying this defect ?

GCC 10

What version of Mbed-os are you using (tag or sha) ?

6.15

What version(s) of tools are you using. List all that apply (E.g. mbed-cli)

latest

How is this defect reproduced ?

difficult without our hardware

[0xc0170]

@ARMmbed/team-st-mcd Please review