drm/i915/gen9: Add boot parameter for disabling DC6

v2: Use _unsafe (Jani)
v3: Allow specifying specific DC-states instead of just DC6 (Imre)

Signed-off-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447682467-6237-3-git-send-email-patrik.jakobsson@linux.intel.com

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d0dccef..6a5dbee 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2642,6 +2642,7 @@ struct i915_params {
        int panel_use_ssc;
        int vbt_sdvo_panel_type;
        int enable_rc6;
+       int enable_dc;
        int enable_fbc;
        int enable_ppgtt;
        int enable_execlists;

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 8ce9a99..07a79b9 100644 (file)
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -32,6 +32,7 @@ struct i915_params i915 __read_mostly = {
        .panel_use_ssc = -1,
        .vbt_sdvo_panel_type = -1,
        .enable_rc6 = -1,
+       .enable_dc = -1,
        .enable_fbc = -1,
        .enable_execlists = -1,
        .enable_hangcheck = true,
@@ -79,6 +80,11 @@ MODULE_PARM_DESC(enable_rc6,
        "For example, 3 would enable rc6 and deep rc6, and 7 would enable everything. "
        "default: -1 (use per-chip default)");
 
+module_param_named_unsafe(enable_dc, i915.enable_dc, int, 0400);
+MODULE_PARM_DESC(enable_dc,
+       "Enable power-saving display C-states. "
+       "(-1=auto [default]; 0=disable; 1=up to DC5; 2=up to DC6)");
+
 module_param_named_unsafe(enable_fbc, i915.enable_fbc, int, 0600);
 MODULE_PARM_DESC(enable_fbc,
        "Enable frame buffer compression for power savings "

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index ad87adc..f816775 100644 (file)
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -417,6 +417,11 @@ static void gen9_set_dc_state(struct drm_i915_private *dev_priv, uint32_t state)
 
        WARN_ON_ONCE(state & ~mask);
 
+       if (i915.enable_dc == 0)
+               state = DC_STATE_DISABLE;
+       else if (i915.enable_dc == 1 && state > DC_STATE_EN_UPTO_DC5)
+               state = DC_STATE_EN_UPTO_DC5;
+
        if (state & DC_STATE_EN_UPTO_DC5_DC6_MASK)
                gen9_set_dc_state_debugmask_memory_up(dev_priv);
 
@@ -525,7 +530,9 @@ static void assert_can_disable_dc6(struct drm_i915_private *dev_priv)
 static void gen9_disable_dc5_dc6(struct drm_i915_private *dev_priv)
 {
        assert_can_disable_dc5(dev_priv);
-       assert_can_disable_dc6(dev_priv);
+
+       if (IS_SKYLAKE(dev_priv) && i915.enable_dc != 0 && i915.enable_dc != 1)
+               assert_can_disable_dc6(dev_priv);
 
        gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
 }
@@ -712,7 +719,7 @@ static void gen9_dc_off_power_well_enable(struct drm_i915_private *dev_priv,
 static void gen9_dc_off_power_well_disable(struct drm_i915_private *dev_priv,
                                           struct i915_power_well *power_well)
 {
-       if (IS_SKYLAKE(dev_priv))
+       if (IS_SKYLAKE(dev_priv) && i915.enable_dc != 0 && i915.enable_dc != 1)
                skl_enable_dc6(dev_priv);
        else
                gen9_enable_dc5(dev_priv);
@@ -724,7 +731,8 @@ static void gen9_dc_off_power_well_sync_hw(struct drm_i915_private *dev_priv,
        if (power_well->count > 0) {
                gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
        } else {
-               if (IS_SKYLAKE(dev_priv))
+               if (IS_SKYLAKE(dev_priv) && i915.enable_dc != 0 &&
+                   i915.enable_dc != 1)
                        gen9_set_dc_state(dev_priv, DC_STATE_EN_UPTO_DC6);
                else
                        gen9_set_dc_state(dev_priv, DC_STATE_EN_UPTO_DC5);