Thread (46 messages) 46 messages, 12 authors, 2015-07-21

Re: [PATCH 2/2] fbcon: expose cursor blink interval via sysfs

From: Scot Doyle <hidden>
Date: 2015-02-25 23:34:33
Also in: linux-api, linux-fbdev
Subsystem: console subsystem, framebuffer layer, the rest, tty layer and serial drivers · Maintainers: Greg Kroah-Hartman, Helge Deller, Linus Torvalds, Jiri Slaby

On Wed, 25 Feb 2015, Pavel Machek wrote:
On Mon 2015-01-26 20:41:53, Scot Doyle wrote:
quoted
The fbcon cursor, when set to blink, is hardcoded to toggle display state
five times per second. Expose this setting via
/sys/class/graphics/fbcon/cursor_blink_ms

Values written to the interface set the approximate time interval in
milliseconds between cursor toggles, from 1 to 32767. Since the interval
is stored internally as a number of jiffies, the millisecond value read
from the interface may not exactly match the entered value.

An outstanding blink timer is reset after a new value is entered.

If the cursor blink is disabled, either via the 'cursor_blink' boolean
setting or some other mechanism, the 'cursor_blink_ms' setting may still
be modified. The new value will be used if the blink is reactivated.

Signed-off-by: Scot Doyle <redacted>
Normally, this would be set by ansi escape sequences, no? We can hide
cursor using them, set its appearance.. makes sense to change timing
value there, too....
									Pavel
Hi Pavel, what about something like this? For example,
"echo -e '\033[16;500]' would set the blink interval to 500 milliseconds.

The duration is stored twice to avoid locking the console in
cursor_timer_handler().

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 6e00572..f117966 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] > 0 &&
+					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/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index b972106..05b1d1a 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -402,7 +402,7 @@ static void cursor_timer_handler(unsigned long dev_addr)
 	struct fbcon_ops *ops = info->fbcon_par;
 
 	queue_work(system_power_efficient_wq, &info->queue);
-	mod_timer(&ops->cursor_timer, jiffies + HZ/5);
+	mod_timer(&ops->cursor_timer, jiffies + ops->cur_blink_jiffies);
 }
 
 static void fbcon_add_cursor_timer(struct fb_info *info)
@@ -417,7 +417,7 @@ static void fbcon_add_cursor_timer(struct fb_info *info)
 
 		init_timer(&ops->cursor_timer);
 		ops->cursor_timer.function = cursor_timer_handler;
-		ops->cursor_timer.expires = jiffies + HZ / 5;
+		ops->cursor_timer.expires = jiffies + ops->cur_blink_jiffies;
 		ops->cursor_timer.data = (unsigned long ) info;
 		add_timer(&ops->cursor_timer);
 		ops->flags |= FBCON_FLAGS_CURSOR_TIMER;
@@ -1309,9 +1309,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
 	if (fbcon_is_inactive(vc, info) || vc->vc_deccm != 1)
 		return;
 
-	if (vc->vc_cursor_type & 0x10)
-		fbcon_del_cursor_timer(info);
-	else
+	ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
+	fbcon_del_cursor_timer(info);
+	if (!(vc->vc_cursor_type & 0x10))
 		fbcon_add_cursor_timer(info);
 
 	ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;
diff --git a/drivers/video/console/fbcon.h b/drivers/video/console/fbcon.h
index 6bd2e0c..7aaa4ea 100644
--- a/drivers/video/console/fbcon.h
+++ b/drivers/video/console/fbcon.h
@@ -70,6 +70,7 @@ struct fbcon_ops {
 	struct fb_cursor cursor_state;
 	struct display *p;
         int    currcon;	                /* Current VC. */
+	int    cur_blink_jiffies;
 	int    cursor_flash;
 	int    cursor_reset;
 	int    blank_state;
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 */
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