From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> We don't want to keep random bits set in DSB_CTRL. Stop the harmful RMW. Also flip the reverse & around to appease my ocd. Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/display/intel_dsb.c | 22 +++++++--------------- drivers/gpu/drm/i915/i915_reg.h | 2 +- 2 files changed, 8 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c index 3d63c1bf1e4f..ebebaf802dee 100644 --- a/drivers/gpu/drm/i915/display/intel_dsb.c +++ b/drivers/gpu/drm/i915/display/intel_dsb.c @@ -73,42 +73,34 @@ struct intel_dsb { static bool is_dsb_busy(struct drm_i915_private *i915, enum pipe pipe, enum dsb_id id) { - return DSB_STATUS & intel_de_read(i915, DSB_CTRL(pipe, id)); + return intel_de_read(i915, DSB_CTRL(pipe, id)) & DSB_STATUS_BUSY; } static bool intel_dsb_enable_engine(struct drm_i915_private *i915, enum pipe pipe, enum dsb_id id) { - u32 dsb_ctrl; - - dsb_ctrl = intel_de_read(i915, DSB_CTRL(pipe, id)); - if (DSB_STATUS & dsb_ctrl) { + if (is_dsb_busy(i915, pipe, id)) { drm_dbg_kms(&i915->drm, "DSB engine is busy.\n"); return false; } - dsb_ctrl |= DSB_ENABLE; - intel_de_write(i915, DSB_CTRL(pipe, id), dsb_ctrl); - + intel_de_write(i915, DSB_CTRL(pipe, id), DSB_ENABLE); intel_de_posting_read(i915, DSB_CTRL(pipe, id)); + return true; } static bool intel_dsb_disable_engine(struct drm_i915_private *i915, enum pipe pipe, enum dsb_id id) { - u32 dsb_ctrl; - - dsb_ctrl = intel_de_read(i915, DSB_CTRL(pipe, id)); - if (DSB_STATUS & dsb_ctrl) { + if (is_dsb_busy(i915, pipe, id)) { drm_dbg_kms(&i915->drm, "DSB engine is busy.\n"); return false; } - dsb_ctrl &= ~DSB_ENABLE; - intel_de_write(i915, DSB_CTRL(pipe, id), dsb_ctrl); - + intel_de_write(i915, DSB_CTRL(pipe, id), 0); intel_de_posting_read(i915, DSB_CTRL(pipe, id)); + return true; } diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index cef9418beec0..ed989e749635 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -8104,7 +8104,7 @@ enum skl_power_gate { #define DSB_TAIL(pipe, id) _MMIO(DSBSL_INSTANCE(pipe, id) + 0x4) #define DSB_CTRL(pipe, id) _MMIO(DSBSL_INSTANCE(pipe, id) + 0x8) #define DSB_ENABLE (1 << 31) -#define DSB_STATUS (1 << 0) +#define DSB_STATUS_BUSY (1 << 0) #define CLKREQ_POLICY _MMIO(0x101038) #define CLKREQ_POLICY_MEM_UP_OVRD REG_BIT(1) -- 2.37.4