[opensuse-kernel] FYI: USB storage (UAS) problems with 3.12 kernels on openSUSE 13.1
Hello, some 13.1 users encountered problems with their USB storage devices that worked fine with 3.11 kernels but fail with recent 3.12 (Evergreen) kernel updates. As this has been already reported twice (bsc#971330, bsc#973663) and potential third report (bsc#978517) waits for confirmation, I wrote a short summary of the situation. This seems to be a generic problem of devices supporting the UAS (USB attached SCSI) protocol which is designed to replace the older USB mass storage Bulk Only Transfer (BOT). Devices supporting UAS are mostly "big" (as in hundreds of gigabytes) external disks. As there used to be a lot of problems with buggy UAS devices, their firmware and drivers, openSUSE 13.1 blacklists uas driver by adding line "blacklist uas" to /etc/modprobe.d/50-blacklist.conf so that regular usb-storage driver is used instead. However, the 3.12 kernel comes from SLE12-SP1 which does not have this general blacklist of uas driver and (at least) some UAS require uas driver to work unless explicitely told otherwise. There are two ways to resolve the issue: 1. (prefered) Disable the "blacklist uas" statement by commenting out the line in /etc/modprobe.d/50-blacklist.conf (insert "#" at the beginning). As the driver might be needed as early as in the initial ramdisk, after editing the file, run "mkinitrd -f" and reboot. 2. Keep uas blacklisted and allow usb-storage to be used for your UAS capable device. This can be achieved by adding line like options usb-storage quirks=0xVVVV:0xPPPP:u with VVVV and PPPP replaced by USB vendor and product id of your device (these can be found in lsusb output on system where the device works) to file /etc/modprobe.d/99-local.conf Again, run "mkinitrd -f" and reboot. There is also the option of providing sysconfig package update disabling the blacklist line but I'm a bit afraid this might break things for people with devices where the support is still buggy (as openSUSE is exposed to much wider range of defices than SLE). Another option would be patching the Evergreen 13.1 kernel to allow using usb-storage for all UAS capable devices without requiring the per-device quirks. I'm not sure how much risk this would be. Michal Kubecek -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org
On Thu, 2016-05-05 at 12:34 +0200, Michal Kubecek wrote:
There is also the option of providing sysconfig package update disabling the blacklist line but I'm a bit afraid this might break things for people with devices where the support is still buggy (as openSUSE is exposed to much wider range of defices than SLE). Another option would be patching the Evergreen 13.1 kernel to allow using usb-storage for all UAS capable devices without requiring the per-device quirks. I'm not sure how much risk this would be.
It would revert to the old behavior. The cost is in performance, not functionality. Regards Oliver -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org
participants (2)
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Michal Kubecek
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Oliver Neukum