4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Paulo Zanoni <[email protected]> commit 2ef32dee97fcf41987722a37eb6ff1a983915e99 upstream. 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: [email protected] Cc: Mahesh Kumar <[email protected]> Signed-off-by: Paulo Zanoni <[email protected]> Reviewed-by: Matt Roper <[email protected]> Link: http://patchwork.freedesktop.org/patch/msgid/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/gpu/drm/i915/intel_pm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3617,6 +3617,9 @@ static int skl_compute_plane_wm(const st 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) { @@ -3637,8 +3640,6 @@ static int skl_compute_plane_wm(const st 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) {
