[v5,2/2] fbcon: expose cursor blink interval via sysfs

Commit Message

Scot Doyle Jan. 30, 2015, 8:44 a.m. UTC

fbcon toggles cursor display state every 200 milliseconds when blinking.
Since users prefer different toggle intervals, expose the interval via
/sys/class/graphics/fbcon/cursor_blink_ms so that it may be customized.

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 <[e-mail]>
---
 drivers/video/console/fbcon.c | 66 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

Comments

Scot Doyle Jan. 30, 2015, 9:35 a.m. UTC | #1

Since users prefer different fbcon cursor blink intervals, allow the
interval to be set via sysfs. The current interval of 200 milliseconds
is retained as the default. Tested with intelfb.

v2:  Use kstrtos16() instead of kstrtoul() and min_t() as suggested by
     Geert Uytterhoeven
v3:  Add error messages as suggested by Tomi Valkeinen
v4:  Add rationale into the patches as suggested by Richard Weinberger
v5:  Return error codes instead of logging error messages (my mistake)
v6:  Uncomment the correct line (my mistake again!)

Scot Doyle (2):
  fbcon: store cursor blink interval in fbcon_ops
  fbcon: expose cursor blink interval via sysfs

 drivers/video/console/fbcon.c | 70 +++++++++++++++++++++++++++++++++++++++++--
 drivers/video/console/fbcon.h |  1 +
 2 files changed, 69 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 7a2030b..f026f65 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -3495,11 +3495,77 @@  err:
 	return count;
 }
 
+static ssize_t show_cursor_blink_ms(struct device *device,
+				    struct device_attribute *attr, char *buf)
+{
+	struct fbcon_ops *ops;
+	int idx, ms = -1;
+
+	if (fbcon_has_exited)
+		return -ENODEV;
+
+	console_lock();
+	idx = con2fb_map[fg_console];
+
+	if (idx != -1 && registered_fb[idx] != NULL) {
+		ops = ((struct fb_info *)registered_fb[idx])->fbcon_par;
+		if (ops != NULL)
+			ms = jiffies_to_msecs(ops->blink_jiffies);
+	}
+
+	console_unlock();
+	return ms < 0 ? -ENODEV : scnprintf(buf, PAGE_SIZE, "%d\n", ms);
+}
+
+static ssize_t store_cursor_blink_ms(struct device *device,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct fb_info *info;
+	struct fbcon_ops *ops;
+	int idx;
+	short ms;
+	int r = -ENODEV;
+
+	if (fbcon_has_exited)
+		return r;
+
+	console_lock();
+	idx = con2fb_map[fg_console];
+
+	if (idx == -1 || registered_fb[idx] == NULL)
+		goto err;
+
+	info = registered_fb[idx];
+	ops = info->fbcon_par;
+
+	if (ops == NULL)
+		goto err;
+
+	if (!kstrtos16(buf, 0, &ms) && ms > 0) {
+		//ops->blink_jiffies = max_t(int, msecs_to_jiffies(ms), 1);
+		ops->blink_jiffies = msecs_to_jiffies(ms);
+		if (info->queue.func == fb_flashcursor &&
+		    ops->flags & FBCON_FLAGS_CURSOR_TIMER) {
+			fbcon_del_cursor_timer(info);
+			fbcon_add_cursor_timer(info);
+		}
+		r = count;
+	} else
+		r = -EINVAL;
+
+err:
+	console_unlock();
+	return r;
+}
+
 static struct device_attribute device_attrs[] = {
 	__ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate),
 	__ATTR(rotate_all, S_IWUSR, NULL, store_rotate_all),
 	__ATTR(cursor_blink, S_IRUGO|S_IWUSR, show_cursor_blink,
 	       store_cursor_blink),
+	__ATTR(cursor_blink_ms, S_IRUGO|S_IWUSR, show_cursor_blink_ms,
+	       store_cursor_blink_ms),
 };
 
 static int fbcon_init_device(void)