• Jiange Zhao's avatar
    drm/amdgpu: Add autodump debugfs node for gpu reset v8 · 728e7e0c
    Jiange Zhao authored
    When GPU got timeout, it would notify an interested part
    of an opportunity to dump info before actual GPU reset.
    
    A usermode app would open 'autodump' node under debugfs system
    and poll() for readable/writable. When a GPU reset is due,
    amdgpu would notify usermode app through wait_queue_head and give
    it 10 minutes to dump info.
    
    After usermode app has done its work, this 'autodump' node is closed.
    On node closure, amdgpu gets to know the dump is done through
    the completion that is triggered in release().
    
    There is no write or read callback because necessary info can be
    obtained through dmesg and umr. Messages back and forth between
    usermode app and amdgpu are unnecessary.
    
    v2: (1) changed 'registered' to 'app_listening'
        (2) add a mutex in open() to prevent race condition
    
    v3 (chk): grab the reset lock to avoid race in autodump_open,
              rename debugfs file to amdgpu_autodump,
              provide autodump_read as well,
              style and code cleanups
    
    v4: add 'bool app_listening' to differentiate situations, so that
        the node can be reopened; also, there is no need to wait for
        completion when no app is waiting for a dump.
    
    v5: change 'bool app_listening' to 'enum amdgpu_autodump_state'
        add 'app_state_mutex' for race conditions:
    	(1)Only 1 user can open this file node
    	(2)wait_dump() can only take effect after poll() executed.
    	(3)eliminated the race condition between release() and
    	   wait_dump()
    
    v6: removed 'enum amdgpu_autodump_state' and 'app_state_mutex'
        removed state checking in amdgpu_debugfs_wait_dump
        Improve on top of version 3 so that the node can be reopened.
    
    v7: move reinit_completion into open() so that only one user
        can open it.
    
    v8: remove complete_all() from amdgpu_debugfs_wait_dump().
    Signed-off-by: default avatarJiange Zhao <Jiange.Zhao@amd.com>
    Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
    Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
    728e7e0c
amdgpu_debugfs.h 1.88 KB