[PATCH v3 09/14] drm/panic: Split draw_panic_plane()
Jocelyn Falempe
jfalempe at redhat.com
Mon Sep 7 14:11:07 PDT 2026
On 9/2/26 14:13, Thomas Zimmermann wrote:
> Move locking and parameters from draw_panic_plane() into the new
> helper drm_panic_display_panic_screen(). Call draw_panic_plane() from
> there.
>
> The new helper drm_panic_display_panic_screen() is now the DRM core's
> interface for displaying a panic screen. The code remaining in
> draw_panic_plane() still does all the heavy lifting. It will become a
> plane helper for DRM drivers.
Thanks, it looks good to me.
Reviewed-by: Jocelyn Falempe <jfalempe at redhat.com>
>
> v2:
> - use panic_type argument in draw_panic_plane() (Sashiko)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> ---
> drivers/gpu/drm/drm_panic.c | 62 ++++++++++++++++++++-----------------
> 1 file changed, 34 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
> index 690e96e8f1f9..624042c42a7f 100644
> --- a/drivers/gpu/drm/drm_panic.c
> +++ b/drivers/gpu/drm/drm_panic.c
> @@ -936,42 +936,25 @@ static void drm_panic_clear_description(void)
> desc_line->txt = NULL;
> }
>
> -static void draw_panic_plane(struct drm_plane *plane, const char *description)
> +static void draw_panic_plane(struct drm_plane *plane, const char *description,
> + enum drm_panic_type panic_type, u32 fg_color, u32 bg_color,
> + unsigned int qr_version)
> {
> struct drm_scanout_buffer sb = { };
> int ret;
> - unsigned long flags;
> -#if defined(CONFIG_DRM_PANIC_FOREGROUND_COLOR)
> - u32 fg_color = CONFIG_DRM_PANIC_FOREGROUND_COLOR;
> -#else
> - u32 fg_color = 0x00ffffff;
> -#endif
> -#if defined(CONFIG_DRM_PANIC_BACKGROUND_COLOR)
> - u32 bg_color = CONFIG_DRM_PANIC_BACKGROUND_COLOR;
> -#else
> - u32 bg_color = 0x00000000;
> -#endif
> -#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> - unsigned int qr_version = panic_qr_version;
> -#else
> - unsigned int qr_version = 0;
> -#endif
> -
> - if (!drm_panic_trylock(plane->dev, flags))
> - return;
>
> ret = plane->helper_private->get_scanout_buffer(plane, &sb);
>
> if (ret || !drm_panic_is_format_supported(sb.format))
> - goto unlock;
> + return;
>
> /* One of these should be set, or it can't draw pixels */
> if (!sb.set_pixel && !sb.pages && iosys_map_is_null(&sb.map[0]))
> - goto unlock;
> + return;
>
> drm_panic_set_description(description);
>
> - ret = draw_panic_dispatch(&sb, drm_panic_type, fg_color, bg_color, qr_version);
> + ret = draw_panic_dispatch(&sb, panic_type, fg_color, bg_color, qr_version);
> if (!ret) {
> /*
> * Only flush if we have a panic screen to display. Otherwise
> @@ -982,9 +965,33 @@ static void draw_panic_plane(struct drm_plane *plane, const char *description)
> }
>
> drm_panic_clear_description();
> +}
>
> -unlock:
> - drm_panic_unlock(plane->dev, flags);
> +static void drm_panic_display_panic_screen(struct drm_plane *plane, const char *description)
> +{
> +#if defined(CONFIG_DRM_PANIC_FOREGROUND_COLOR)
> + u32 fg_color = CONFIG_DRM_PANIC_FOREGROUND_COLOR;
> +#else
> + u32 fg_color = 0x00ffffff;
> +#endif
> +#if defined(CONFIG_DRM_PANIC_BACKGROUND_COLOR)
> + u32 bg_color = CONFIG_DRM_PANIC_BACKGROUND_COLOR;
> +#else
> + u32 bg_color = 0x00000000;
> +#endif
> +#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> + unsigned int qr_version = panic_qr_version;
> +#else
> + unsigned int qr_version = 0;
> +#endif
> + struct drm_device *dev = plane->dev;
> + unsigned long flags;
> +
> + if (drm_panic_trylock(dev, flags)) {
> + draw_panic_plane(plane, description, drm_panic_type,
> + fg_color, bg_color, qr_version);
> + drm_panic_unlock(dev, flags);
> + }
> }
>
> static struct drm_plane *to_drm_plane(struct kmsg_dumper *kd)
> @@ -997,10 +1004,9 @@ static void drm_panic(struct kmsg_dumper *dumper, struct kmsg_dump_detail *detai
> struct drm_plane *plane = to_drm_plane(dumper);
>
> if (detail->reason == KMSG_DUMP_PANIC)
> - draw_panic_plane(plane, detail->description);
> + drm_panic_display_panic_screen(plane, detail->description);
> }
>
> -
> /*
> * DEBUG FS, This is currently unsafe.
> * Create one file per plane, so it's possible to debug one plane at a time.
> @@ -1017,7 +1023,7 @@ static ssize_t debugfs_trigger_write(struct file *file, const char __user *user_
> if (kstrtobool_from_user(user_buf, count, &run) == 0 && run) {
> struct drm_plane *plane = file->private_data;
>
> - draw_panic_plane(plane, "Test from debugfs");
> + drm_panic_display_panic_screen(plane, "Test from debugfs");
> }
> return count;
> }
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