udlfb: Enable fb_defio by default

Enables page fault based detection of mmap writes to the framebuffer,
which allows standard fbdev apps (like the generic fbdev xorg driver)
to work on DisplayLink devices.

Not all bugs are shaken out of the fb_defio path of udlfb, but it's
tantalizingly close, so this seems a good time to enable by default.

Alternatively, option can be disabled when running with an xorg driver
that can more directly communicate damaged regions of the framebuffer
via IOCTL. This is a simpler, higher perf option, when available.

Signed-off-by: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/video/udlfb.c b/drivers/video/udlfb.c
index 2341b275e815..2b694e1c73cb 100644
--- a/drivers/video/udlfb.c
+++ b/drivers/video/udlfb.c
@@ -61,7 +61,7 @@ MODULE_DEVICE_TABLE(usb, id_table);
 
 /* module options */
 static int console;   /* Optionally allow fbcon to consume first framebuffer */
-static int fb_defio;  /* Optionally enable experimental fb_defio mmap support */
+static int fb_defio = 1;  /* Detect mmap writes using page faults */
 static int shadow = 1; /* Optionally disable shadow framebuffer */
 
 /* dlfb keeps a list of urbs for efficient bulk transfers */
@@ -1951,7 +1951,7 @@ module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
 MODULE_PARM_DESC(console, "Allow fbcon to consume first framebuffer found");
 
 module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
-MODULE_PARM_DESC(fb_defio, "Enable fb_defio mmap support. *Experimental*");
+MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
 
 module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
 MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");