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udlfb: Enable fbcon access to framebuffer by default

Signed-off-by: Bernie Thompson <>
Signed-off-by: Florian Tobias Schandinat <>
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1 parent 9f811b7 commit 4aa7faffe44bda5db54c214f5b3f789ec805cb9b @bernieplug bernieplug committed with schandinat Aug 21, 2011
Showing with 8 additions and 6 deletions.
  1. +6 −4 Documentation/fb/udlfb.txt
  2. +2 −2 drivers/video/udlfb.c
10 Documentation/fb/udlfb.txt
@@ -107,16 +107,18 @@ fb_defio Make use of the fb_defio (CONFIG_FB_DEFERRED_IO) kernel
Disable when running with X server that supports reporting
changed regions via ioctl, as this method is simpler,
more stable, and higher performance.
+ default: fb_defio=1
-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.
+console Allow fbcon to attach to udlfb provided framebuffers.
+ Can be disabled if fbcon and other clients
+ (e.g. X with --shared-vt) are in conflict.
+ default: console=1
shadow Allocate a 2nd framebuffer to shadow what's currently across
the USB bus in device memory. If any pixels are unchanged,
do not transmit. Spends host memory to save USB transfers.
Enabled by default. Only disable on very low memory systems.
+ default: shadow=1
Sysfs Attributes
4 drivers/video/udlfb.c
@@ -60,7 +60,7 @@ static struct usb_device_id id_table[] = {
MODULE_DEVICE_TABLE(usb, id_table);
/* module options */
-static int console; /* Optionally allow fbcon to consume first framebuffer */
+static int console = 1; /* Allow fbcon to open framebuffer */
static int fb_defio = 1; /* Detect mmap writes using page faults */
static int shadow = 1; /* Optionally disable shadow framebuffer */
@@ -1948,7 +1948,7 @@ static int dlfb_submit_urb(struct dlfb_data *dev, struct urb *urb, size_t len)
module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
-MODULE_PARM_DESC(console, "Allow fbcon to consume first framebuffer found");
+MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");

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