From: Animesh Manna <[email protected]>

Restore CMTG registers after DC6 exit, as they lose their values
in the low-power state.

v2: Introduce intel_cmtg_restore() instead of calling multiple cmtg
functions. [Uma]

Signed-off-by: Animesh Manna <[email protected]>
---
 drivers/gpu/drm/i915/display/intel_cmtg.c     | 21 +++++++++++++----
 .../drm/i915/display/intel_display_power.c    | 23 +++++++++++++++++++
 .../drm/i915/display/intel_display_power.h    |  2 ++
 3 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cmtg.c 
b/drivers/gpu/drm/i915/display/intel_cmtg.c
index 8684d2ec2f83..ae59d7e755f3 100644
--- a/drivers/gpu/drm/i915/display/intel_cmtg.c
+++ b/drivers/gpu/drm/i915/display/intel_cmtg.c
@@ -391,20 +391,33 @@ static void intel_cmtg_set_hwgb(const struct 
intel_crtc_state *crtc_state)
        intel_de_write(display, CMTG_HW_GB(cpu_transcoder), val);
 }
 
+static void intel_cmtg_restore(const struct intel_crtc_state *crtc_state)
+{
+       intel_cmtg_set_clk_select(crtc_state);
+       intel_cmtg_set_timings(crtc_state, MODESET);
+       intel_cmtg_set_vrr_timings(crtc_state);
+       intel_cmtg_set_vrr_ctl(crtc_state);
+       intel_cmtg_set_m_n(crtc_state);
+}
+
 void intel_cmtg_program(struct intel_atomic_state *state)
 {
+       struct intel_display *display = to_intel_display(state);
        struct intel_crtc *crtc;
        struct intel_crtc_state *new_crtc_state;
+       bool dc3co_to_dc6 = 
intel_display_power_get_and_reset_dc3co_to_dc6(display);
 
        for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state) {
                bool modeset = intel_crtc_needs_modeset(new_crtc_state);
 
                if (!intel_cmtg_is_allowed(new_crtc_state))
                        continue;
-               /*
-                * TODO: CMTG needs to be restored on DC6 exit.
-                */
-               if (modeset && new_crtc_state->hw.active && 
!crtc->cmtg.enabled) {
+
+               if ((modeset || dc3co_to_dc6) &&
+                   new_crtc_state->hw.active && !crtc->cmtg.enabled) {
+                       if (dc3co_to_dc6)
+                               intel_cmtg_restore(new_crtc_state);
+
                        intel_cmtg_enable_sync(new_crtc_state);
                        intel_cmtg_set_hwgb(new_crtc_state);
                        intel_cmtg_enable_ddi(new_crtc_state);
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c 
b/drivers/gpu/drm/i915/display/intel_display_power.c
index 2e51dfcd5dce..9783257651d2 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -285,6 +285,19 @@ sanitize_target_dc_state(struct intel_display *display,
        return target_dc_state;
 }
 
+bool intel_display_power_get_and_reset_dc3co_to_dc6(struct intel_display 
*display)
+{
+       struct i915_power_domains *power_domains = &display->power.domains;
+       bool ret;
+
+       mutex_lock(&power_domains->lock);
+       ret = power_domains->dc3co_to_dc6;
+       power_domains->dc3co_to_dc6 = false;
+       mutex_unlock(&power_domains->lock);
+
+       return ret;
+}
+
 /**
  * intel_display_power_set_target_dc_state - Set target dc state.
  * @display: display device
@@ -300,6 +313,7 @@ void intel_display_power_set_target_dc_state(struct 
intel_display *display,
        struct i915_power_well *power_well;
        bool dc_off_enabled;
        struct i915_power_domains *power_domains = &display->power.domains;
+       u32 old_target_dc_state;
 
        mutex_lock(&power_domains->lock);
        power_well = lookup_power_well(display, SKL_DISP_DC_OFF);
@@ -320,8 +334,17 @@ void intel_display_power_set_target_dc_state(struct 
intel_display *display,
        if (!dc_off_enabled)
                intel_power_well_enable(display, power_well);
 
+       old_target_dc_state =  power_domains->target_dc_state;
        power_domains->target_dc_state = state;
 
+       /*
+        * CMTG must be restored explicitly after DC6 exit. The dc3co_to_dc6
+        * flag helps CMTG determine whether restoration is required.
+        */
+       if (old_target_dc_state == DC_STATE_EN_DC3CO &&
+           power_domains->target_dc_state == DC_STATE_EN_UPTO_DC6)
+               power_domains->dc3co_to_dc6 = true;
+
        if (!dc_off_enabled)
                intel_power_well_disable(display, power_well);
 
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.h 
b/drivers/gpu/drm/i915/display/intel_display_power.h
index 56dc89eed3f8..b9c9b68072af 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.h
+++ b/drivers/gpu/drm/i915/display/intel_display_power.h
@@ -138,6 +138,7 @@ struct i915_power_domains {
         */
        bool initializing;
        bool display_core_suspended;
+       bool dc3co_to_dc6;
        int power_well_count;
 
        u32 dc_state;
@@ -179,6 +180,7 @@ void intel_display_power_sanitize_state(struct 
intel_display *display);
 
 void intel_display_power_suspend_late(struct intel_display *display, bool 
s2idle);
 void intel_display_power_resume_early(struct intel_display *display);
+bool intel_display_power_get_and_reset_dc3co_to_dc6(struct intel_display 
*display);
 void intel_display_power_set_target_dc_state(struct intel_display *display,
                                             u32 state);
 u32 intel_display_power_get_current_dc_state(struct intel_display *display);
-- 
2.43.0

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