[Intel-gfx] [PATCH 02/23] HAX drm/i915: Disable FEC entirely for now

[Maarten Lankhorst]

I get a permanent FIFO underrun when enabling FEC with big joiner,
so for now disable it.

It seems that even at 1024x768 resolution without bigjoiner we don't
get a working configuration. Flag is set but vblank timing shows that
vblanks are delivered slightly faster, so the extra overhead we
calculated for data M/N goes unused.

Not-Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 4dfb78dc7fa2..02242a16640b 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1877,7 +1877,8 @@ static bool intel_dp_source_supports_dsc(struct intel_dp *intel_dp,
 static bool intel_dp_supports_dsc(struct intel_dp *intel_dp,
 				  const struct intel_crtc_state *pipe_config)
 {
-	if (!intel_dp_is_edp(intel_dp) && !pipe_config->fec_enable)
+	/* HACK: Disable FEC until we solved FIFO underruns */
+	if (!intel_dp_is_edp(intel_dp) && !pipe_config->fec_enable && 0)
 		return false;
 
 	return intel_dp_source_supports_dsc(intel_dp, pipe_config) &&
@@ -2024,8 +2025,9 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	int pipe_bpp;
 	int ret;
 
+	/* HACK: Disable FEC until we solved FIFO underruns */
 	pipe_config->fec_enable = !intel_dp_is_edp(intel_dp) &&
-		intel_dp_supports_fec(intel_dp, pipe_config);
+		intel_dp_supports_fec(intel_dp, pipe_config) && 0;
 
 	if (!intel_dp_supports_dsc(intel_dp, pipe_config))
 		return -EINVAL;
-- 
2.20.1