• Kalyan Thota's avatar
    drm/msm/dpu: ensure device suspend happens during PM sleep · ca8199f1
    Kalyan Thota authored
    "The PM core always increments the runtime usage counter
    before calling the ->suspend() callback and decrements it
    after calling the ->resume() callback"
    
    DPU and DSI are managed as runtime devices. When
    suspend is triggered, PM core adds a refcount on all the
    devices and calls device suspend, since usage count is
    already incremented, runtime suspend was not getting called
    and it kept the clocks on which resulted in target not
    entering into XO shutdown.
    
    Add changes to force suspend on runtime devices during pm sleep.
    
    Changes in v1:
     - Remove unnecessary checks in the function
        _dpu_kms_disable_dpu (Rob Clark).
    
    Changes in v2:
     - Avoid using suspend_late to reset the usagecount
       as suspend_late might not be called during suspend
       call failures (Doug).
    
    Changes in v3:
     - Use force suspend instead of managing device usage_count
       via runtime put and get API's to trigger callbacks (Doug).
    
    Changes in v4:
     - Check the return values of pm_runtime_force_suspend and
       pm_runtime_force_resume API's and pass appropriately (Doug).
    
    Changes in v5:
     - With v4 patch, test cycle has uncovered issues in device resume.
    
       On bubs: cmd tx failures were seen as SW is sending panel off
       commands when the dsi resources are turned off.
    
       Upon suspend, DRM driver will issue a NULL composition to the
       dpu, followed by turning off all the HW blocks.
    
       v5 changes will serialize the NULL commit and resource unwinding
       by handling them under PM prepare and PM complete phases there by
       ensuring that clks are on when panel off commands are being
       processed.
    
    Changes in v6:
    - Use drm_mode_config_helper_suspend/resume() instead of legacy API
      drm_atomic_helper_suspend/resume() (Doug).
    
      Trigger runtime callbacks from the suspend/resume call to turn
      off the resources.
    
    Changes in v7:
    - Add "__maybe_unused" to the functions to avoid compilation
      failures. Cleanup unnecessary configs (Doug).
    Signed-off-by: default avatarKalyan Thota <kalyan_t@codeaurora.org>
    Reviewed-by: default avatarDouglas Anderson <dianders@chromium.org>
    Signed-off-by: default avatarRob Clark <robdclark@chromium.org>
    ca8199f1
dpu_kms.c 28.1 KB