path: root/Documentation/fb/udlfb.txt
diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2011-10-30 22:30:01 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2011-10-30 22:30:01 (GMT)
commitacff987d94cbdb4049f3706bed1f1792f8ef6837 (patch)
tree36bded977aab5d80cf9aeb5467f83dd554a25d01 /Documentation/fb/udlfb.txt
parentce949717b559709423c1ef716a9db16d1dcadaed (diff)
parentb57287ba497b63a0d87a058631bbddfed9392e9f (diff)
Merge branch 'fbdev-next' of git://github.com/schandinat/linux-2.6
* 'fbdev-next' of git://github.com/schandinat/linux-2.6: (270 commits) video: platinumfb: Add __devexit_p at necessary place drivers/video: fsl-diu-fb: merge diu_pool into fsl_diu_data drivers/video: fsl-diu-fb: merge diu_hw into fsl_diu_data drivers/video: fsl-diu-fb: only DIU modes 0 and 1 are supported drivers/video: fsl-diu-fb: remove unused panel operating mode support drivers/video: fsl-diu-fb: use an enum for the AOI index drivers/video: fsl-diu-fb: add several new video modes drivers/video: fsl-diu-fb: remove broken screen blanking support drivers/video: fsl-diu-fb: move some definitions out of the header file drivers/video: fsl-diu-fb: fix some ioctls video: da8xx-fb: Increased resolution configuration of revised LCDC IP OMAPDSS: picodlp: add missing #include <linux/module.h> fb: fix au1100fb bitrot. mx3fb: fix NULL pointer dereference in screen blanking. video: irq: Remove IRQF_DISABLED smscufx: change edid data to u8 instead of char OMAPDSS: DISPC: zorder support for DSS overlays OMAPDSS: DISPC: VIDEO3 pipeline support OMAPDSS/OMAP_VOUT: Fix incorrect OMAP3-alpha compatibility setting video/omap: fix build dependencies ... Fix up conflicts in: - drivers/staging/xgifb/XGI_main_26.c Changes to XGIfb_pan_var() - drivers/video/omap/{lcd_apollon.c,lcd_ldp.c,lcd_overo.c} Removed (or in the case of apollon.c, merged into the generic DSS panel in drivers/video/omap2/displays/panel-generic-dpi.c)
Diffstat (limited to 'Documentation/fb/udlfb.txt')
1 files changed, 27 insertions, 12 deletions
diff --git a/Documentation/fb/udlfb.txt b/Documentation/fb/udlfb.txt
index 7fdde2a..57d2f29 100644
--- a/Documentation/fb/udlfb.txt
+++ b/Documentation/fb/udlfb.txt
@@ -87,23 +87,38 @@ 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.
-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.
+ 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.
+ default: fb_defio=1
+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
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