udlfb: Enable fb_defio by default

[~andy/linux] / Documentation / fb / udlfb.txt

diff --git a/Documentation/fb/udlfb.txt b/Documentation/fb/udlfb.txt
index 473ceed9e4eb4be0bbe836b8d9fc1049ce6ae0ec..c6d90a6fb90190aa72d038b1454867396be31949 100644 (file)
--- a/Documentation/fb/udlfb.txt
+++ b/Documentation/fb/udlfb.txt
@@ -87,20 +87,28 @@ Special configuration for udlfb is usually unnecessary. There are a few
 options, however.
 
 From the command line, pass options to modprobe
-modprobe udlfb defio=1 console=1
+modprobe udlfb fb_defio=0 console=1 shadow=1
 
-Or for permanent option, create file like /etc/modprobe.d/options with text
-options udlfb defio=1 console=1
+Or modify options on the fly at /sys/module/udlfb/parameters directory via
+sudo nano fb_defio
+change the parameter in place, and save the file.
 
-Accepted options:
+Unplug/replug USB device to apply with new settings
+
+Or for permanent option, create file like /etc/modprobe.d/udlfb.conf with text
+options udlfb fb_defio=0 console=1 shadow=1
+
+Accepted boolean options:
 
 fb_defio       Make use of the fb_defio (CONFIG_FB_DEFERRED_IO) kernel
                module to track changed areas of the framebuffer by page faults.
-               Standard fbdev applications that use mmap but that do not
-               report damage, may be able to work with this enabled.
-               Disabled by default because of overhead and other issues.
+               Standard fbdev applications that use mmap but that do not
+               report damage, should be able to work with this enabled.
+               Disable when running with X server that supports reporting
+               changed regions via ioctl, as this method is simpler,
+               more stable, and higher performance.
 
-console                Allow fbcon to attach to udlfb provided framebuffers. This
+console        Allow fbcon to attach to udlfb provided framebuffers. This
                is disabled by default because fbcon will aggressively consume
                the first framebuffer it finds, which isn't usually what the
                user wants in the case of USB displays.