Plugable’s USB 2.0 Graphics Adapter (DisplayLink DL-195)

Posted on 07. Mar, 2010 by Bernie Thompson in UGA-2K-A

Plugable’s new USB 2.0 Graphics Adapter is now available on Amazon.com.

The DisplayLink DL-195 chip inside this adapter is the best high-end chip out there for adding a display over USB. And because it pushes USB 2.0 and analog VGA to their limits, it isn’t likely to be beaten by any other chip in the USB 2.0 generation.

For this new adapter from Plugable, we wanted to offer that high-end choice, and also make sure that everything else about the adapter package itself meets or beats any alternative out there.

  • The Plugable UGA-2K-A includes a DVI->HDMI adapter (in addition to the usual DVI->VGA adapter)
  • The latest drivers are available on Windows Update and from displaylink.com
  • Open source available, so there’ll be new software written for this device, even years from now
  • Public problem reporting and support, so you can always get the full story about the product
  • Amazon’s fast shipping and A-to-z guarantee on your purchase

In future posts, we’ll cover some of the cool things this device can do by enabling many displays on any PC (things like create the ultimate day-traders’ war-room, with many displays built around a single laptop).

Until then, you can read more about the product launch in the stuffily worded press release here. And more on the product page at http://plugable.com/products/uga-2k-a/.

DisplayLink Linux Rotation

Posted on 02. Jan, 2010 by Bernie Thompson in udlfb

With a kernel framebuffer driver that supports defio (like the version of udlfb in testing at git.plugable.com), it’s possible to use the standard xf86-video-fbdev X driver, rather than a custom DisplayLink one.

One interesting gain is xf86-video-fbdev supports rotation with a custom option (note it disables DGA and xrandr when it rotated mode).

To enable, in the xorg.conf “Device” section, add a Rotate option, setting it to CW, CCW, or UD.

Section "Device"
  Identifier "dl"
  Driver "fbdev"
  Option "rotate" "CCW"
  Option "fbdev" "/dev/fb1"
EndSection

One downside is rendering is significantly slower, as the extra work of rotation is done at the X level and the page-fault behavior of defio means even small updates refresh much of the screen. Here’s some numbers that can be compared to earlier posts (in non-rotate mode):

bernie@bernie-aspireone:~/git/misc-udlfb$ ./udlfb-perf.sh fb0 gtkperf -a
Xlib:  extension "RANDR" missing on display ":3.0".
GtkPerf 0.40 - Starting testing: Fri Jan  1 09:47:20 2010
 
GtkEntry - time:  0.00
GtkComboBox - time:  3.73
GtkComboBoxEntry - time:  2.08
GtkSpinButton - time:  0.49
GtkProgressBar - time:  0.69
GtkToggleButton - time:  0.47
GtkCheckButton - time:  0.44
GtkRadioButton - time:  0.79
GtkTextView - Add text - time:  2.30
GtkTextView - Scroll - time:  1.24
GtkDrawingArea - Lines - time:  4.14
GtkDrawingArea - Circles - time:  4.56
GtkDrawingArea - Text - time:  4.11
GtkDrawingArea - Pixbufs - time:  0.90
 ---
Total time: 25.96
 
Quitting..
 
model name      : Intel(R) Atom(TM) CPU N270   @ 1.60GHz
model name      : Intel(R) Atom(TM) CPU N270   @ 1.60GHz
cpu MHz         : 800.000
cpu MHz         : 800.000
MemTotal:        2052144 kB
Framebuffer Mode: 1920,1080
 
Rendered bytes:  1238913024 (total pixels * Bpp)
Identical bytes: 1070725304 (skipped via shadow buffer check)
sent bytes:      125732225 (compressed usb data, including overhead)
K CPU cycles:    7478653 (transpired, may include context switches)
 
% pixels found to be unchanged: 86.00 %
Compression of changed pixels : 25.00 %
Total CPU cycles spent per input pixel: 6
Total CPU cycles spent per output pixel: 59
USB Mbps: 35.52 (theoretical USB 2.0 peak 480)
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