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| author | Jiri Slaby <jslaby@suse.cz> | 2016-06-23 14:34:24 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-06-25 19:04:48 +0300 |
| commit | a4bedd019ec9690c1e5c7105509a2ef52c5ae3e0 (patch) | |
| tree | 2f46a5d25289b391d924940c8c6951369dde37b5 /include/linux/console_struct.h | |
| parent | 1b0ec88ac1cb0413a717bc3cefea72d6f2533672 (diff) | |
| download | linux-a4bedd019ec9690c1e5c7105509a2ef52c5ae3e0.tar.xz | |
vt: document vc_data by example
All those members of vc_data are each explained in short. But it needs
an example for one to understand the whole picture.
So add an ascii art depicting the most important vc_data members.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/console_struct.h')
| -rw-r--r-- | include/linux/console_struct.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h index e329ee2667e1..5fa605c93428 100644 --- a/include/linux/console_struct.h +++ b/include/linux/console_struct.h @@ -21,6 +21,38 @@ struct uni_pagedir; #define NPAR 16 +/* + * Example: vc_data of a console that was scrolled 3 lines down. + * + * Console buffer + * vc_screenbuf ---------> +----------------------+-. + * | initializing W | \ + * | initializing X | | + * | initializing Y | > scroll-back area + * | initializing Z | | + * | | / + * vc_visible_origin ---> ^+----------------------+-: + * (changes by scroll) || Welcome to linux | \ + * || | | + * vc_rows --->< | login: root | | visible on console + * || password: | > (vc_screenbuf_size is + * vc_origin -----------> || | | vc_size_row * vc_rows) + * (start when no scroll) || Last login: 12:28 | / + * v+----------------------+-: + * | Have a lot of fun... | \ + * vc_pos -----------------|--------v | > scroll-front area + * | ~ # cat_ | / + * vc_scr_end -----------> +----------------------+-: + * (vc_origin + | | \ EMPTY, to be filled by + * vc_screenbuf_size) | | / vc_video_erase_char + * +----------------------+-' + * <---- 2 * vc_cols -----> + * <---- vc_size_row -----> + * + * Note that every character in the console buffer is accompanied with an + * attribute in the buffer right after the character. This is not depicted + * in the figure. + */ struct vc_data { struct tty_port port; /* Upper level data */ |