DisplayLink Linux Rotation

[updated 8/14/2011 with latest udlfb info] The xorg generic fbdev driver (xf86-video-fbdev) supports rotation with a custom option (note it disables DGA and xrandr when it rotated mode). DisplayLink devices can use this driver two ways: With the udlfb fb_defio option enabled to detect framebuffer writes based on page faults With the fbdev xorg server […]

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Linux USB quirks on 2.6.32

Doing development on udlfb on Linux 2.6.32, crossed paths with these two quirks. The usb_skeleton.c sample driver appears to run afoul of this problem, resulting in a warn_on during bulk transfer completion, if done the way the sample recommends. Because completion routines can be called with irqs disabled, usb_buffer_free on dma-ready buffers can’t be called […]

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Take your pick: standard or custom displaylink X drivers both work now

[update May 3, 2012: Support for using fb_defio and the standard, generic X fbdev driver is enabled by default, working, and stable with kernel 3.3 (at least). You’ll get lower CPU consumption and latency with DAMAGE notifications, but on many systems (especially higher end), fbdev is great. And because not everything supports DAMAGE, generic fbdev […]

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DisplayLink Linux performance metrics

For a USB virtual graphics solution, performance is critical. For the Linux drivers for DisplayLink devices, there are several patches and alternative implementations that are tough to evaluate, compare (and merge) without hard data. It would be great to know what compression ratio we’re getting, how much data is being sent over USB, etc. So, […]

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Setting up USB multiseat with DisplayLink on Linux (GDM up to 2.20)

Soon, we’ll be able to plug inexpensive zero-state USB docks/terminals into new Linux systems, and a new graphical login will pop up in a completely plug and play fashion. Many users can then simultaneously share any single Linux PC. This is great for education, libraries, internet cafes, etc — anywhere where you have clusters of […]

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Microsoft Windows Multipoint Server 2010 Announced

Microsoft has announced their Windows solution that’s similar to Linux multiseat: Windows Server Multipoint 2010. Architecturally, it’s actually similar to running several VNC clients in loopback mode on the same Linux server. See Microsoft’s “Unlimited Potential” blog for more information from Microsoft. “Unlimited” is over the top, but there’s certainly unfulfilled potential for multiseat (my […]

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udlfb 0.4.0

[Update Dec 29, 2011: udlfb was promoted from the staging to the mainline kernel tree in 2.6.38. And in kernel 3.3 pagefault detection and console are enabled by default. See all our udlfb posts for the latest news.] [Update March 14, 2010: udlfb versions have moved to being released with the Linux kernel. Update on […]

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