In AtaAtapiPassThruStop(), if the device has been operating in AHCI mode, we unmap the DMA buffers and then disable the device (including bus master DMA). The order of these actions is wrong; we shouldn't unmap DMA buffers until bus master DMA is turned off. Reverse the steps. Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Eric Dong <eric.dong@intel.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Star Zeng <star.zeng@intel.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com> Reviewed-by: Star Zeng <star.zeng@intel.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>