It wasn't terribly clear from the bspec's wording, but after discussion
with the hardware folks, it turns out that we need to preserve the
pre-existing contents of the MBUS ABOX control register when
initializing a few specific bits.
Bspec: 49213
Bspec: 50096
Fixes: 4cb4585e5a7f ("drm/i915/icl: initialize MBus during display init")
Cc: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_display_power.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 6d91e180db99..529319c962e8 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -4504,14 +4504,18 @@ static void icl_dbuf_disable(struct drm_i915_private *dev_priv)
static void icl_mbus_init(struct drm_i915_private *dev_priv)
{
- u32 val;
+ u32 mask, val;
+ mask = MBUS_ABOX_BT_CREDIT_POOL1_MASK |
+ MBUS_ABOX_BT_CREDIT_POOL2_MASK |
+ MBUS_ABOX_B_CREDIT_MASK |
+ MBUS_ABOX_BW_CREDIT_MASK;
val = MBUS_ABOX_BT_CREDIT_POOL1(16) |
- MBUS_ABOX_BT_CREDIT_POOL2(16) |
- MBUS_ABOX_B_CREDIT(1) |
- MBUS_ABOX_BW_CREDIT(1);
+ MBUS_ABOX_BT_CREDIT_POOL2(16) |
+ MBUS_ABOX_B_CREDIT(1) |
+ MBUS_ABOX_BW_CREDIT(1);
- intel_de_write(dev_priv, MBUS_ABOX_CTL, val);
+ intel_de_rmw(dev_priv, MBUS_ABOX_CTL, mask, val);
}
static void hsw_assert_cdclk(struct drm_i915_private *dev_priv)
--
2.24.1
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