@@ -44,6 +44,7 @@ struct fblog_fb {
static DEFINE_MUTEX(fblog_registration_lock);
static struct fblog_fb *fblog_fbs[FB_MAX];
+static bool active = 1;
#define to_fblog_dev(_d) container_of(_d, struct fblog_fb, dev)
@@ -115,6 +116,40 @@ static void fblog_close(struct fblog_fb *fb, bool kill_dev)
mutex_unlock(&fb->lock);
}
+static ssize_t fblog_dev_active_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct fblog_fb *fb = to_fblog_dev(dev);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ !!test_bit(FBLOG_OPEN, &fb->flags));
+}
+
+static ssize_t fblog_dev_active_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ struct fblog_fb *fb = to_fblog_dev(dev);
+ unsigned long num;
+ int ret = 0;
+
+ num = simple_strtoul(buf, NULL, 10);
+
+ mutex_lock(&fb->info->lock);
+ if (num)
+ ret = fblog_open(fb);
+ else
+ fblog_close(fb, false);
+ mutex_unlock(&fb->info->lock);
+
+ return ret ? ret : count;
+}
+
+static DEVICE_ATTR(active, S_IRUGO | S_IWUSR | S_IWGRP, fblog_dev_active_show,
+ fblog_dev_active_store);
+
/*
* fblog framebuffer list
* The fblog_fbs[] array contains all currently registered framebuffers. If a
@@ -148,6 +183,7 @@ static void fblog_do_unregister(struct fb_info *info)
fblog_fbs[info->node] = NULL;
fblog_close(fb, true);
+ device_remove_file(&fb->dev, &dev_attr_active);
device_del(&fb->dev);
put_device(&fb->dev);
}
@@ -156,6 +192,7 @@ static void fblog_do_register(struct fb_info *info, bool force)
{
struct fblog_fb *fb;
int ret;
+ bool do_open = true;
fb = fblog_fbs[info->node];
if (fb && fb->info != info) {
@@ -186,7 +223,18 @@ static void fblog_do_register(struct fb_info *info, bool force)
return;
}
- fblog_open(fb);
+ ret = device_create_file(&fb->dev, &dev_attr_active);
+ if (ret) {
+ pr_err("fblog: cannot create sysfs entry");
+ /* do not open fb if we cannot create control file */
+ do_open = false;
+ }
+
+ if (!active)
+ do_open = false;
+
+ if (do_open)
+ fblog_open(fb);
}
static void fblog_register(struct fb_info *info, bool force)
@@ -321,6 +369,9 @@ static void __exit fblog_exit(void)
}
}
+module_param(active, bool, S_IRUGO | S_IWUSR | S_IWGRP);
+MODULE_PARM_DESC(active, "Activate fblog by default");
+
module_init(fblog_init);
module_exit(fblog_exit);
MODULE_LICENSE("GPL");
fblog is mainly useful during boot, reboot, panics and maintenance. In all cases you often want to control which monitors are used for console output. Moreover, in multi-seat environments it is desireable to reduce system-overhead by not drawing the console to all framebuffers. Two mechanisms to select framebuffers for fblog are added: 1) "active" module parameter: This parameter selects whether new framebuffers are opened automatically. By default this is on, that is, all framebuffers are automatically used by fblog during boot. By passing fblog.active=0 you can deactivate this. The init process can set this to 0 via /sys/modules/fblog/parameters/active, too. However, this does not affect already available and used framebuffers in any way. 2) "active" sysfs attribute for each fblog object. Reading this value returns whether a framebuffer is currently active. Writing it opens/closes the framebuffer. This allows runtime control which fbs are used. For instance, init can set these to 0 after bootup. Signed-off-by: David Herrmann <dh.herrmann@googlemail.com> --- drivers/video/console/fblog.c | 53 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 52 insertions(+), 1 deletion(-)