Subject: Re: [PATCH 0/5] drm/rockchip: vop2: Fix layer cfg done timeout on multi-output setups

From: Andy Yan <[email-masked]>
Date: Mon, 1 Jun 2026 18:54:25 +0800

Hello Cristian,

On 5/5/26 02:23, Cristian Ciocaltea wrote:
> On RK3588/RK3568 boards with multiple active display outputs, start/stop
> transitions may trigger a timeout during overlay layer configuration:
> 
>    rockchip-drm display-subsystem: [drm] *ERROR* wait layer cfg done timeout
> 
> The shared OVL_LAYER_SEL and OVL_PORT_SEL shadow registers are committed
> to the active configuration at the vsync of whichever Video Port is
> selected by LAYERSEL_REGDONE_SEL.  When two Video Ports race through
> atomic commits, rk3568_vop2_setup_layer_mixer() has two issues that
> cause the wait to poll for a value the hardware might not be able to
> produce.
> 
> Patch 1 fixes passing the wrong target to the wait function, since the
> expected value was already overwritten with the current VP's new
> layer_sel before reaching the wait.
> 
> Patch 2 moves the wait before the LAYERSEL_REGDONE_SEL switch, so the
> previous VP's vsync can still latch the pending configuration.
> 
> Patches 3 through 5 contain only minor follow-up cleanup.
> 
> Signed-off-by: Cristian Ciocaltea <[email-masked]>

Thank you very much for your work, these fixes all look sensible.
However, I haven't been able to construct a scenario via weston that
reproduce these issues. Could you please tell me how you triggered them?

> ---
> Cristian Ciocaltea (5):
>        drm/rockchip: vop2: Fix wrong wait target in layer cfg done check
>        drm/rockchip: vop2: Wait for layer cfg done before switching LAYERSEL_REGDONE_SEL
>        drm/rockchip: vop2: Delay old_{layer|port}_sel updates in setup_layer_mixer()
>        drm/rockchip: vop2: Drop redundant zero-init in setup_layer_mixer()
>        drm/rockchip: vop2: Use vop2->old_layer_sel directly in wait_for_layer_cfg_done()
> 
>   drivers/gpu/drm/rockchip/rockchip_vop2_reg.c | 46 +++++++++++++---------------
>   1 file changed, 22 insertions(+), 24 deletions(-)
> ---
> base-commit: d4c14903bf5e28e740516c4fbb7db01e0dedf3af
> change-id: 20260504-vop2-layer-cfg-tmout-73617a0a103c
> 
>