On Thu, Jan 16, 2020 at 05:58:37PM -0800, José Roberto de Souza wrote:
TGL timeouts when disabling MST transcoder and fifo underruns over MST transcoders are fixed when setting TRANS_DDI_MODE_SELECT to 0(HDMI mode) during the disable sequence.
Although BSpec disable sequence don't require this step it is a harmless change and it is also done by Windows driver. Anyhow HW team was notified about that but it can take some time to documentation to be updated.
A case that always lead to those issues is:
- do a modeset enabling pipe A and pipe B in the same MST stream
leaving A as master
- disable pipe A, promote B as master doing a full modeset in A
- enable pipe A, changing the master transcoder back to A(doing a
full modeset in B)
- Pow: underruns and timeouts
The transcoders involved will only work again when complete disabled and their power wells turned off causing a reset in their registers.
Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Matt Roper matthew.d.roper@intel.com Signed-off-by: José Roberto de Souza jose.souza@intel.com
drivers/gpu/drm/i915/display/intel_ddi.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c index 32ea3c7e8b62..82e90f271974 100644 --- a/drivers/gpu/drm/i915/display/intel_ddi.c +++ b/drivers/gpu/drm/i915/display/intel_ddi.c @@ -1997,6 +1997,7 @@ void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state
val = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder)); val &= ~TRANS_DDI_FUNC_ENABLE;
- val &= ~TRANS_DDI_MODE_SELECT_MASK;
Feels a bit early since IIRC we still leave a bunch of other stuff enabled/selected here. In fact we don't seem to be clearing the DDI select anywhere at all? That one I would be more suspicious of than the mode. But maybe we should just clear both somewhere? I would suggest it should be when we clear the port select finally.
if (INTEL_GEN(dev_priv) >= 12) { if (!intel_dp_mst_is_master_trans(crtc_state)) -- 2.25.0