From c725161924f9a5872a3e53b73345a6026a5c170e Mon Sep 17 00:00:00 2001 From: Matt Roper Date: Thu, 27 Feb 2020 16:43:19 -0800 Subject: [PATCH] drm/i915: Program MBUS with rmw during initialization 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 Signed-off-by: Matt Roper Link: https://patchwork.freedesktop.org/patch/msgid/20200204011032.582737-1-matthew.d.roper@intel.com Reviewed-by: Matt Atwood (cherry picked from commit 837b63e6087838d0f1e612d448405419199d8033) Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20200228004320.127142-1-matthew.d.roper@intel.com --- drivers/gpu/drm/i915/display/intel_display_power.c | 16 +++++++++++----- 1 file changed, 11 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 21561acfa3ac..ae532e45e36b 100644 --- a/drivers/gpu/drm/i915/display/intel_display_power.c +++ b/drivers/gpu/drm/i915/display/intel_display_power.c @@ -4466,13 +4466,19 @@ 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; - val = MBUS_ABOX_BT_CREDIT_POOL1(16) | - MBUS_ABOX_BT_CREDIT_POOL2(16) | - MBUS_ABOX_B_CREDIT(1) | - MBUS_ABOX_BW_CREDIT(1); + mask = MBUS_ABOX_BT_CREDIT_POOL1_MASK | + MBUS_ABOX_BT_CREDIT_POOL2_MASK | + MBUS_ABOX_B_CREDIT_MASK | + MBUS_ABOX_BW_CREDIT_MASK; + val = I915_READ(MBUS_ABOX_CTL); + val &= ~mask; + val |= MBUS_ABOX_BT_CREDIT_POOL1(16) | + MBUS_ABOX_BT_CREDIT_POOL2(16) | + MBUS_ABOX_B_CREDIT(1) | + MBUS_ABOX_BW_CREDIT(1); I915_WRITE(MBUS_ABOX_CTL, val); } -- 2.11.0