Hi mark, ? 2017/7/31 17:49, Mark Yao ??: > Iommu would get page fault with following path: > vop_disable: > 1, disable all windows and set vop config done > 2, vop enter to standy, all windows not works, but their registers > are not clean, when you read window's enable bit, may found the > window is enable. > > vop_enable: > 1, memcpy(vop->regsbak, vop->regs, len) > save current vop registers to vop->regsbak, then you can found > window is enable on regsbak. > 2, VOP_WIN_SET(vop, win, gate, 1); > force enable window gate, but gate and enable are on same > hardware register, then window enable bit rewrite to vop hardware. > 3, vop power on, and vop might try to scan destroyed buffer, > then iommu get page fault. > > Move windows disable after vop regsbak restore, then vop regsbak mechanism > would keep tracing the modify, everything would be safe. > > Signed-off-by: Mark Yao <mark.yao at rock-chips.com> > --- > drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 33 +++++++++++++---------------- > 1 file changed, 15 insertions(+), 18 deletions(-) > Reviewed-by: Sandy huang <sandy.huang at rock-chips.com>
