Created attachment 144954 [details]
Screenshot from callgraph excerpt

With Linux 5.3-rc3 and pm-graph’s `sleepgraph.py` [1] measuring suspend times
on the Dell OptiPlex 5040 with an external AMD graphics card, the driver needs
2.1 seconds to suspend the device, which is too long.

    $ lspci -nn -s 01:
    01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc.
[AMD/ATI] Oland XT [Radeon HD 8670 / R7 250/350] [1002:6610] (rev 81)
    01:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] Cape
Verde/Pitcairn HDMI Audio [Radeon HD 7700/7800 Series] [1002:aab0]

Here is the time:

    0000:01:00.0 suspend (2170.017 ms @ 5037.143762 to 5039.313779)

Looking into the call graph, 1.4 s are spent in `ttm_bo_evict_mm`.

    ttm_bo_evict_mm [ttm] (1438.050 ms @ 5037.601941)

As you can see in the attached screenshot, there are some
`ttm_bo_handle_move_mem` call which take several milliseconds adding up to the
long time.

    - ttm_mem_evict_first [ttm] (304.860 ms @ 5037.705809)
        _raw_spin_lock
        mutex_trylock (0.000 ms @ 5037.705809)
        + ttm_bo_del_from_lru [ttm]
        - ttm_bo_evict [ttm] (304.857 ms @ 5037.705810)
            amdgpu_evict_flags [amdgpu] (0.000 ms @ 5037.705810)
            ttm_bo_mem_space [ttm] (0.001 ms @ 5037.705811)
            ttm_bo_handle_move_mem [ttm] (304.853 ms @ 5037.705812)

[1]: https://github.com/intel/pm-graph