Re: [PATCH] fbcon: don't suspend/resume when vc is graphics mode

[Helge Deller <deller@gmx.de>]

Hello Lu,

On 4/30/26 08:01, yaolu@kylinos.cn wrote:
> From: Lu Yao <yaolu@kylinos.cn>
> 
> Don't need to do suspend/resume for fbcon in graphic mode.
> 
> Doing this may cause error, eg:
>    At the beginning, starting the Xorg with single screen and then an
>    external screen was plugged in. After logging out in Xorg, fbdev
>    info may using screen which is connected later on for info always
>    using first connected connector in list in func 'drm_setup_crtcs_fb'.
>    Then, S3 executed, fbcon found that the information did not match
>    and do atomic to switch fb. However, Xorg will not re-bind the crtc
>    fb but continues doing ioctl. At this time, the fb is incorrect.


Do you still have the possibility to test this issue?

  
> Signed-off-by: Lu Yao <yaolu@kylinos.cn>
> ---
>   drivers/video/fbdev/core/fbcon.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index b0e3e765360d..450e690d0bd2 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -2602,8 +2602,9 @@ void fbcon_suspended(struct fb_info *info)
>   		return;
>   	vc = vc_cons[par->currcon].d;
>   
> -	/* Clear cursor, restore saved data */
> -	fbcon_cursor(vc, false);
> +	/* Don't need to clear cursor and restore saved data in graphic mode */
> +	if (vc->vc_mode != KD_GRAPHICS)
> +		fbcon_cursor(vc, false);

I think checking for "== KD_TEXT" is probably better.
And, maybe using con_is_visible(vc).
So:

+	if (con_is_visible(vc) && (vc->vc_mode == KD_TEXT))
+		fbcon_cursor(vc, false);


>   void fbcon_resumed(struct fb_info *info)
> @@ -2615,7 +2616,9 @@ void fbcon_resumed(struct fb_info *info)
>   		return;
>   	vc = vc_cons[par->currcon].d;
>   
> -	update_screen(vc);
> +	/* Graphics mode is managed by userspace */
> +	if (vc->vc_mode != KD_GRAPHICS)

here the same check as above... ?

Helge