Re: [PATCH v4 2/2] arm64: dts: rockchip: add RK3588 DP carrier from Theobroma Systems

[Quentin Schulz <quentin.schulz@cherry.de>]

Hi Heiko,

On 10/10/25 12:50 AM, Heiko Stuebner wrote:
> From: Heiko Stuebner <heiko.stuebner@cherry.de>
> 
> The DisplayPort carrier is a very simple baseboard only providing serial,
> ethernet and a displayport output.
> 
> But its main functionality is that it routes the Analogix eDP controller
> to this DisplayPort output, which allows to test that controller simply
> by hooking it up to a suitable monitor.
> 
> The Analogix-DP controller supports eDP 1.3 and DP 1.2, so can drive
> both eDP displays as well as full DP monitors. It does not support DP+
> so passive DP-to-HDMI adapters won't work.
> 
> Signed-off-by: Heiko Stuebner <heiko.stuebner@cherry.de>
> Link: https://lore.kernel.org/r/20250723190904.37792-3-heiko@sntech.de

Please remove the Link trailer for v5 (if there's one) :)

I only have one remark: the device is stuck when shutting down or 
rebooting after this one line in the logs (can be shown by adding 
initcall_debug to the kernel command line)

[   21.973452] arm-smmu-v3 fc900000.iommu: shutdown

It only reboots by chance, after ~1m30s, because the watchdog is started 
before rebooting and never triggered again.

If I add:

&mmu600_pcie {
         status = "disabled";
};

then the device reboots just fine. So we either temporarily disable it 
or we try to fix the origin of the issue.

As reported to Damon today on the v2 of this series, I tested with
https://lore.kernel.org/all/20250930090920.131094-1-damon.ding@rock-chips.com/
https://lore.kernel.org/all/20250930094251.131314-1-damon.ding@rock-chips.com/ 
(patches 14-18 of the previous thread)
https://lore.kernel.org/all/20251009193028.4952-1-heiko@sntech.de/
https://lore.kernel.org/linux-rockchip/20251008133135.3745785-1-heiko@sntech.de/

and DP works as expected (minus some (I deem to be) minor issues).

Cheers,
Quentin