• Zhao Yakui's avatar
    drm/i915: Use the coarse ping-pong mechanism based on drm fd to dispatch the BSD command on BDW GT3 · a8ebba75
    Zhao Yakui authored
    The BDW GT3 has two independent BSD rings, which can be used to process the
    video commands. To be simpler, it is transparent to user-space driver/middle.
    Instead the kernel driver will decide which ring is to dispatch the BSD video
    command.
    
    As every BSD ring is powerful, it is enough to dispatch the BSD video command
    based on the drm fd. In such case it can play back video stream while encoding
    another video stream. The coarse ping-pong mechanism is used to determine
    which BSD ring is used to dispatch the BSD video command.
    
    V1->V2: Follow Daniel's comment and use the simple ping-pong mechanism.
    This is only to add the support of dual BSD rings on BDW GT3 machine.
    The further optimization will be considered in another patch set.
    
    V2->V3: Follow Daniel's comment to use the struct_mutext instead of
    atomic_t during determining which ring can be used to dispatch Video command.
    Reviewed-by: default avatarImre Deak <imre.deak@intel.com>
    Signed-off-by: default avatarZhao Yakui <yakui.zhao@intel.com>
    Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    a8ebba75
i915_drv.h 80.8 KB