From fee0fddc1dc114039bf9aed9fdeeecdc1949cdc7 Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Thu, 1 Mar 2018 15:44:57 +0200 Subject: drm/i915/gen9, gen10: Disable FBC on planes with a misaligned Y-offset Enabling FBC on a plane having a Y-offset that isn't divisible by 4 may cause pipe FIFO underruns and flickers, so disable FBC on such a config. I tried the followings to work around the issue: - enable each HW work around in ILK_DPFC_CHICKEN - disable each compression algorithm in ILK_DPFC_CONTROL - disable low-power watermarks None of the above got rid of the problem. I haven't found this issue in the Bspec/WA database either. Besides the igt testcase below (yet to be merged) an easy way to reproduce the issue is to enable a plane with FBC and a plane Y-offset not aligned to 4 and then just enable/disable FBC in a loop, keeping the plane enabled. I could trigger the problem on BXT/GLK/SKL/CNL, so assume for now that it's only present on GEN9 and GEN10. v2: (Ville) - Run the test/apply the WA on CNL as well. - Use IS_GEN() instead of INTEL_GEN(). - Fix spelling. Cc: Paulo Zanoni Cc: Ville Syrjälä Testcase: igt/kms_plane/plane-clipping-pipe-A-planes Signed-off-by: Imre Deak Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20180301134457.13974-1-imre.deak@intel.com --- drivers/gpu/drm/i915/intel_fbc.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/gpu/drm') diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c index 38b036c499d9..38a5535a5c63 100644 --- a/drivers/gpu/drm/i915/intel_fbc.c +++ b/drivers/gpu/drm/i915/intel_fbc.c @@ -859,6 +859,17 @@ static bool intel_fbc_can_activate(struct intel_crtc *crtc) return false; } + /* + * Work around a problem on GEN9+ HW, where enabling FBC on a plane + * having a Y offset that isn't divisible by 4 causes FIFO underrun + * and screen flicker. + */ + if (IS_GEN(dev_priv, 9, 10) && + (fbc->state_cache.plane.adjusted_y & 3)) { + fbc->no_fbc_reason = "plane Y offset is misaligned"; + return false; + } + return true; } -- cgit v1.2.3-55-g7522