[PATCH v2 1/3] vt: add cursor blink interval escape sequence

Scot Doyle
2015-03-26T13:54:39Z

Add an escape sequence to specify the current console's cursor blink
interval. The interval is specified as a number of milliseconds until
the next cursor display state toggle, from 50 to 65535. /proc/loadavg
did not show a difference with a one msec interval, but the lower
bound is set to 50 msecs since slower hardware wasn't tested.

Store the interval in the vc_data structure for later access by fbcon,
initializing the value to fbcon's current hardcoded value of 200 msecs.

Signed-off-by: Scot Doyle <lkml14-enLWO88E2pdl57MIdRCFDg@public.gmane.org>
Acked-by: Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>
---
drivers/tty/vt/vt.c | 9 +++++++++
include/linux/console_struct.h | 1 +
2 files changed, 10 insertions(+)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 6e00572..ab1f173 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -135,6 +135,7 @@ const struct consw *conswitchp;
*/
#define DEFAULT_BELL_PITCH 750
#define DEFAULT_BELL_DURATION (HZ/8)
+#define DEFAULT_CURSOR_BLINK_MS 200

struct vc vc_cons [MAX_NR_CONSOLES];

@@ -1590,6 +1591,13 @@ static void setterm_command(struct vc_data *vc)
case 15: /* activate the previous console */
set_console(last_console);
break;
+ case 16: /* set cursor blink duration in msec */
+ if (vc->vc_npar >= 1 && vc->vc_par[1] >= 50 &&
+ vc->vc_par[1] <= USHRT_MAX)
+ vc->vc_cur_blink_ms = vc->vc_par[1];
+ else
+ vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
+ break;
}
}

@@ -1717,6 +1725,7 @@ static void reset_terminal(struct vc_data *vc, int do_clear)

vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
vc->vc_bell_duration = DEFAULT_BELL_DURATION;
+ vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;

gotoxy(vc, 0, 0);
save_cur(vc);
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index e859c98..e329ee2 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -104,6 +104,7 @@ struct vc_data {
unsigned int vc_resize_user; /* resize request from user */
unsigned int vc_bell_pitch; /* Console bell pitch */
unsigned int vc_bell_duration; /* Console bell duration */
+ unsigned short vc_cur_blink_ms; /* Cursor blink duration */
struct vc_data **vc_display_fg; /* [!] Ptr to var holding fg console for this display */
struct uni_pagedir *vc_uni_pagedir;
struct uni_pagedir **vc_uni_pagedir_loc; /* [!] Location of uni_pagedir variable for this console */
--
2.1.0