Re: [PATCH v6 2/2] fbcon: expose cursor blink interval via sysfs

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 <redacted>
---
 drivers/video/console/fbcon.c | 65 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 7a2030b..7baa333 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c

@@ -3495,11 +3495,76 @@ 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;