Xorg without root rights now available in Fedora

Xorg without root rights is now available in Fedora rawhide. Currently the suid root wrapper which is intended for ums compatbility is configured to run the server as root by default even on kms using setups, because starting Xorg as a normal user requires the display manager to set up its session and tty as it can no longer do that itself, and non of the display managers are ready to do this yet.

Still you can test running Xorg as user if you want, create a file called /etc/X11/Xwrapper.config with the following line in there: "needs_root_rights = auto" the default for "needs_root_rights" currently is "yes" rather then "auto" because of the display managers not being ready yet. Then switch to a text console (ctrl + alt + F2) log in as a regular user and run: "startx". Now do "ps aux" and you should see a (second) Xorg process running as a normal user.

If you're running rawhide and have some time to spare I would appreciate it if you can give this a try, and let me know if you see any issues running Xorg as normal user. Don't forget to remove the /etc/X11/Xwrapper.config file you've created after testing so that you don't break your graphical login screen.

UAS: USB Attached SCSI now available in the 3.15 kernel, qemu USB-3.0 compatibility coming up

At the end of 2013 I've spend 2 full months working on getting XHCI streams support and the UAS driver in the Linux kernel, which uses streams into shape. With the release of the 3.15 kernel this work now is available for end users to use.

This is good news for anyone who cares about performance of USB connected harddisks / ssds. The old usb mass-storage protocol is well known for its poor performance. UAS however allows NCQ and thus allows effectively using the full USB-3 bandwidth. If you've an UAS capable harddisk enclosure then all you need is a 3.15 kernel build with the UAS driver enabled and you should instantly get better performance. Note that most harddisk enclosures, including USB-3 enclosures do not support UAS, so if you want to use UAS double check before buying a harddisk enclosure.

One use-case of UAS I love is to have a 2.5" ssd with a full Fedora rawhide install with me so that when people ask me about hardware compatilibty issues they are having, I can simply plug in the ssd to there laptop boot rawhide and see if having the latest kernel + xorg fixes things. For a decently priced UAS capable 2.5" hdd enclosure search ebay for: "sedna usb 3.0 2.5 inch hdd enclosure". when shopping for UAS enabled devices, always check that the device description mentions UAS or UASP.

Besides UAS support, the 3.15 kernel also features support for using USB-3 bulk streams from userspace through usbfs. To use this you need the just released libusb-1.0.19 release. One use case of USB-3 bulk streams from userspace is using these for usb-redirection in qemu. With the upcoming 2.1 qemu release this will be supported allowing the use if usb-3 redirection with uas devices from within a qemu vm. This will be supported with both qemu's host usb redirection, as well as spice's network usb redirection. This means that starting with qemu-2.1 qemu's USB redirection features full USB-3.0 compatibility.