https://bugs.freedesktop.org/show_bug.cgi?id=83708
--- Comment #9 from Jack zduo006@163.com --- I solved that problem by use readl()/writel() func to access cpu virtual address insteand of set address directly. such as use readl(&msg[1]) instead of msg_type=msg[1]. and use the l/b endian transfer. But the new error ocurred (error message) . radeon:GPU lockup cp stall for ... more than... I try to change the lockup timeout to longer but no use. I don't know why??