Re: [PATCH 04/12] drm/panic: Return errno codes if panic output fails

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] draw_panic_screen_qr_code() ignores the return value of its fallback function draw_panic_screen_user() and unconditionally returns 0.
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--- Patch [4]: [PATCH 04/12] drm/panic: Return errno codes if panic output fails ---
commit 8764682ca919f839ac40d09290f5a67bb03da8dc
Author: Thomas Zimmermann <tzimmermann@suse.de>

drm/panic: Return errno codes if panic output fails

This commit updates the panic output helpers to return errno codes on
failure. This allows the driver to avoid flushing the display if an error
occurs, preserving the unflushed display output for debugging.

> diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
> --- a/drivers/gpu/drm/drm_panic.c
> +++ b/drivers/gpu/drm/drm_panic.c
[ ... ]
> @@ -814,10 +818,11 @@ static int _draw_panic_screen_qr_code(struct drm_scanout_buffer *sb)
>  	return 0;
>  }
>  
> -static void draw_panic_screen_qr_code(struct drm_scanout_buffer *sb)
> +static int draw_panic_screen_qr_code(struct drm_scanout_buffer *sb)
>  {
>  	if (_draw_panic_screen_qr_code(sb))
>  		draw_panic_screen_user(sb);
> +	return 0;

[Severity: Medium]
Should this return the error code from draw_panic_screen_user() if the
fallback also fails?

Because this unconditionally returns 0, draw_panic_dispatch() will report
success even if both _draw_panic_screen_qr_code() and the fallback fail.
This causes draw_panic_plane() to still flush the display buffer, which
might overwrite the unflushed output this patch aims to preserve.

>  }
>  #else
>  static void drm_panic_qr_init(void) {};

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Sashiko AI review · https://sashiko.dev/#/patchset/20260818125012.468092-1-tzimmermann@suse.de?part=4