Public bug reported: On AMD SB700/SB800/Hudson-2/3 platforms, USB EHCI controller may read/write to memory space not allocated to USB controller if there is longer than normal latency on DMA read encountered. In this condition the exposure will be encountered only if the driver has following format of Periodic Frame List link pointer structure:
For any idle periodic schedule, the Frame List link pointers that have the T-bit set to 1 intending to terminate the use of frame list link pointer as a physical memory pointer. Idle periodic schedule Frame List Link pointer shoule be in the following format to avoid the issue: Frame list link pointer should be always contains a valid pointer to a inactive QHead with T-bit set to 0. Steps to Reproduce: It is SW workaround of HW issue, it is difficult to reproduce from driver point. Patch has been accepted by EHCI maintainer: http://www.spinics.net/lists/linux-usb/msg38405.html http://www.spinics.net/lists/linux-usb/msg38414.html We will provide the git link here once it is available, suppose the patch will appear from kernel 2.6.37 if everything is ok. We hope the issue will be fixed by Ubuntu 11.04 if its kernel is not up to date enough. ** Affects: linux (Ubuntu) Importance: Undecided Status: New -- Ubuntu 11.04: EHCI: AMD periodic frame list table quirk https://bugs.launchpad.net/bugs/672951 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
