Hello Jasem,

The purpose of this patch is to control the mirror lock function without the remote serial shutter.
Only the main USB.

1) I just put the "/dev/null" device to get the mirror lock timer option in ekos.
The if statement:
if (! strcmp(gphoto->bulb_port,"/dev/null") == 0)
prevent the opening of /dev/null as i did not use the gphoto->bulb_port

2) In the gphoto_driver.c i use the foolowing sequence:
(The Canon camera is set with mirror lock to ON, and rotation dial to Bulb)
a) gphoto_set_widget_num (gphoto, gphoto->bulb_widget, 2); // I push the button and the mirror is now UP
b) gphoto_set_widget_num (gphoto, gphoto->bulb_widget, 4); // I release the button
c) usleep (msec * 1000); // i sleep with the mirror locked until the end of timer set in ekos

3) After the mirror lock done the capture will begin with another
gphoto_set_widget_num (gphoto, gphoto->bulb_widget, 2);

I will acquire a Canon 6D soon and will test this code portion.