intel_set_pch_fifo_underrun_reporting — set PCH fifo underrun reporting state
|struct drm_i915_private * dev_priv,|
|enum transcoder pch_transcoder,|
i915 device instance
the PCH transcoder (same as pipe on IVB and older)
whether underruns should be reported or not
This function makes us disable or enable PCH fifo underruns for a specific PCH transcoder. Notice that on some PCHs (e.g. CPT/PPT), disabling FIFO underrun reporting for one transcoder may also disable all the other PCH error interruts for the other transcoders, due to the fact that there's just one interrupt mask/enable bit for all the transcoders.
Returns the previous state of underrun reporting.