2008-02-15 17:25:45

by Samuel Thibault

Subject: [PATCH] VT notifier extension for accessibility

Some accessibility modules need to be able to catch the output on the
console before the VT interpretation, and possibly swallow it.

Signed-off-by: Samuel Thibault <[email protected]>
From: Karl Dahlke <[email protected]>

--- include/linux/notifier.h 2008-02-15 08:44:10.000000000 -0500
+++ include/linux/notifier.h.new 2008-02-15 09:58:00.000000000 -0500
@@ -247,6 +247,7 @@ extern struct blocking_notifier_head reb
#define VT_DEALLOCATE 0x0002 /* Console will be deallocated */
#define VT_WRITE 0x0003 /* A char got output */
#define VT_UPDATE 0x0004 /* A bigger update occurred */
+#define VT_PREWRITE 0x0005 /* A char is about to be written to the console */

#endif /* __KERNEL__ */
#endif /* _LINUX_NOTIFIER_H */
--- drivers/char/vt.c 2008-02-15 08:43:35.000000000 -0500
+++ drivers/char/vt.c.new 2008-02-15 10:11:14.000000000 -0500
@@ -2053,6 +2053,7 @@ static int do_con_write(struct tty_struc
unsigned long draw_from = 0, draw_to = 0;
struct vc_data *vc;
unsigned char vc_attr;
+ struct vt_notifier_param param;
uint8_t rescan;
uint8_t inverse;
uint8_t width;
@@ -2112,6 +2113,8 @@ static int do_con_write(struct tty_struc
if (IS_FG(vc))
hide_cursor(vc);

+ param.vc = vc;
+
while (!tty->stopped && count) {
int orig = *buf;
c = orig;
@@ -2200,6 +2203,10 @@ rescan_last_byte:
tc = vc->vc_translate[vc->vc_toggle_meta ? (c | 0x80) : c];
}

+ param.c = tc;
+ if (atomic_notifier_call_chain(&vt_notifier_list, VT_PREWRITE, &param) == NOTIFY_STOP)
+ continue;
+
/* If the original code was a control character we
* only allow a glyph to be displayed if the code is
* not normally used (such as for cursor movement) or

2008-02-23 08:14:14

by Andrew Morton

Subject: Re: [PATCH] VT notifier extension for accessibility

On Fri, 15 Feb 2008 18:25:16 +0100 Samuel Thibault <[email protected]> wrote:

> Some accessibility modules need to be able to catch the output on the
> console before the VT interpretation, and possibly swallow it.
>
> Signed-off-by: Samuel Thibault <[email protected]>
> From: Karl Dahlke <[email protected]>

Please put the From: at the very top of the changelog when providing
attribution.

Did we have a signed-off-by: from Karl?

> --- include/linux/notifier.h 2008-02-15 08:44:10.000000000 -0500
> +++ include/linux/notifier.h.new 2008-02-15 09:58:00.000000000 -0500

Please prepare patches in `patch -p1' form, thanks.

2008-02-23 13:49:22

by Samuel Thibault

Subject: Re: [PATCH] VT notifier extension for accessibility

Andrew Morton, le Sat 23 Feb 2008 00:07:13 -0800, a ?crit :
> Did we have a signed-off-by: from Karl?

He didn't give any.

Samuel