From: Paulo Zanoni Date: Tue, 8 Nov 2016 20:22:11 +0000 (-0200) Subject: drm/i915/gen9: fix the WM memory bandwidth WA for Y tiling cases X-Git-Tag: v4.10-rc1~154^2~21^2~75 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2ef32dee97fcf41987722a37eb6ff1a983915e99;p=karo-tx-linux.git drm/i915/gen9: fix the WM memory bandwidth WA for Y tiling cases The previous spec version said "double Ytile planes minimum lines", and I interpreted this as referring to what the spec calls "Y tile minimum", but in fact it was referring to what the spec calls "Minimum Scanlines for Y tile". I noticed that Mahesh Kumar had a different interpretation, so I sent and email to the spec authors and got clarification on the correct meaning. Also, BSpec was updated and should be clear now. Fixes: ee3d532fcb64 ("drm/i915/gen9: unconditionally apply the memory bandwidth WA") Cc: stable@vger.kernel.org Cc: Mahesh Kumar Signed-off-by: Paulo Zanoni Reviewed-by: Matt Roper Link: http://patchwork.freedesktop.org/patch/msgid/1478636531-6081-1-git-send-email-paulo.r.zanoni@intel.com --- diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 35c4afd2e143..f1ef9559014c 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3626,6 +3626,9 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv, y_min_scanlines = 4; } + if (apply_memory_bw_wa) + y_min_scanlines *= 2; + plane_bytes_per_line = width * cpp; if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED || fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED) { @@ -3646,8 +3649,6 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv, plane_blocks_per_line); y_tile_minimum = plane_blocks_per_line * y_min_scanlines; - if (apply_memory_bw_wa) - y_tile_minimum *= 2; if (fb->modifier[0] == I915_FORMAT_MOD_Y_TILED || fb->modifier[0] == I915_FORMAT_MOD_Yf_TILED) {