• Nicholas Kazlauskas's avatar
    drm/amd/display: Support reading hw state from debugfs file · 46659a83
    Nicholas Kazlauskas authored
    [Why]
    
    Logging hardware state can be done by triggering a write to the
    debugfs file. It would also be useful to be able to read the hardware
    state from the debugfs file to be able to generate a clean log without
    timestamps.
    
    [How]
    
    Usage: cat /sys/kernel/debug/dri/0/amdgpu_dm_dtn_log
    
    Threading is an obvious concern when dealing with multiple debugfs
    operations and blocking on global state in dm or dc seems unfavorable.
    
    Adding an extra parameter for the debugfs log context state is the
    implementation done here. Existing code that made use of DTN_INFO
    and its associated macros needed to be refactored to support this.
    
    We don't know the size of the log in advance so it reallocates the
    log string dynamically. Once the log has been generated it's copied
    into the user supplied buffer for the debugfs. This allows for seeking
    support but it's worth nothing that unlike triggering output via
    dmesg the hardware state might change in-between reads if your buffer
    size is too small.
    Signed-off-by: default avatarNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
    Reviewed-by: default avatarJordan Lazare <Jordan.Lazare@amd.com>
    Acked-by: default avatarLeo Li <sunpeng.li@amd.com>
    Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
    46659a83
dm_services.h 11.9 KB