From: dw kim <dongwon....@intel.com>

Correct bit mapping of EUs in 'eu_disable' fuse register
for each subslice is (each word represents one subslice),

bit # 7   6   5   4   3   2   1   0
EU # 11  10   9   8   3   2   1   0

In BXT, each subslice has 6 EUs at most, which are EU0~EU2
and EU8~EU10 (EU11 and EU3 don't exist). Therefore, correct
eu_mask should be 0x77 to cover all EUs in each subslice that
can be possibly enabled.

Cc: Matthew D Roper <matthew.d.ro...@intel.com>
Signed-off-by: dw kim <dongwon....@intel.com>
---
 drivers/gpu/drm/i915/i915_dma.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 066a0ef..810f148 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -633,13 +633,21 @@ static void gen9_sseu_info_init(struct drm_device *dev)
 
        /*
         * BXT has a single slice. BXT also has at most 6 EU per subslice,
-        * and therefore only the lowest 6 bits of the 8-bit EU disable
-        * fields are valid.
+        * and bit mappings vs EU # in eu_disable fuse value in one subslice
+         * is like this;
+         *
+         *  Bit # 7   6   5   4   3   2   1   0
+         *  EU # 11  10   9   8   3   2   1   0
+         *
+         * Since only EUs with number "0, 1, 2, 8, 9, 10" are available in
+         * each subslice in BXT, bits in eu_mask should also be set according
+         * to this mapping, therefore, eu_mask = 0x77.
        */
+
        if (IS_BROXTON(dev)) {
                s_max = 1;
                eu_max = 6;
-               eu_mask = 0x3f;
+               eu_mask = 0x77;
        }
 
        info = (struct intel_device_info *)&dev_priv->info;
-- 
1.9.1

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