Re: [PATCH v2] drm/loongson: stop to set get_vblank_timestamp for LS7A1000 CRTC

[Icenowy Zheng]

在 2026-03-21六的 17:28 +0800，Icenowy Zheng写道：
> As there's no known hardware capability about querying vblank on the
> LS7A1000 display controller, setting get_vblank_timestamp will
> mislead the
> kernel about the support of DC-backed high precision vblank query.
> 
> Drop this function pointer in the CRTC function table for LS7A1000.
> 
> This solves a kernel warning when booting Linux 7.0-rc3 on a
> Loongson-3A4000+LS7A1000 Haier Boyue G51 laptop (with injected EDID
> for
> replicating the display timing set by the firmware).
> 
> Signed-off-by: Icenowy Zheng <zhengxingda@xxxxxxxxxxx>

Oh forgot to attach when crafting v2:

```
Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
```

> ---
> Changes in v2:
> - Re-formatted Loongson product model numbers per request from
> Huacai.
> 
>  drivers/gpu/drm/loongson/lsdc_crtc.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/loongson/lsdc_crtc.c
> b/drivers/gpu/drm/loongson/lsdc_crtc.c
> index 587fbe285e9ef..b3af8e0cdb15f 100644
> --- a/drivers/gpu/drm/loongson/lsdc_crtc.c
> +++ b/drivers/gpu/drm/loongson/lsdc_crtc.c
> @@ -721,7 +721,6 @@ static const struct drm_crtc_funcs
> ls7a1000_crtc_funcs = {
>  	.late_register = lsdc_crtc_late_register,
>  	.enable_vblank = lsdc_crtc_enable_vblank,
>  	.disable_vblank = lsdc_crtc_disable_vblank,
> -	.get_vblank_timestamp =
> drm_crtc_vblank_helper_get_vblank_timestamp,
>  	.atomic_print_state = lsdc_crtc_atomic_print_state,
>  };
>