drm/radeon/dpm: implement vblank_too_short callback for btc

Check if we can switch the mclk during the vblank time otherwise
we may get artifacts on the screen when the mclk changes.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

3 files changed, 17 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/btc_dpm.c b/drivers/gpu/drm/radeon/btc_dpm.c
index 91567448c55d..0bfd55e08820 100644
--- a/drivers/gpu/drm/radeon/btc_dpm.c
+++ b/drivers/gpu/drm/radeon/btc_dpm.c
@@ -2059,6 +2059,19 @@ static void btc_init_stutter_mode(struct radeon_device *rdev)
         }
 }
 
+bool btc_dpm_vblank_too_short(struct radeon_device *rdev)
+{
+        struct rv7xx_power_info *pi = rv770_get_pi(rdev);
+        u32 vblank_time = r600_dpm_get_vblank_time(rdev);
+        u32 switch_limit = pi->mem_gddr5 ? 450 : 100;
+
+        if (vblank_time < switch_limit)
+                return true;
+        else
+                return false;
+
+}
+
 static void btc_apply_state_adjust_rules(struct radeon_device *rdev,
                                          struct radeon_ps *rps)
 {
@@ -2068,7 +2081,8 @@ static void btc_apply_state_adjust_rules(struct radeon_device *rdev,
         u32 mclk, sclk;
         u16 vddc, vddci;
 
-        if (rdev->pm.dpm.new_active_crtc_count > 1)
+        if ((rdev->pm.dpm.new_active_crtc_count > 1) ||
+            btc_dpm_vblank_too_short(rdev))
                 disable_mclk_switching = true;
         else
                 disable_mclk_switching = false;
diff --git a/drivers/gpu/drm/radeon/radeon_asic.c b/drivers/gpu/drm/radeon/radeon_asic.c
index e73026393a46..c42b3674b426 100644
--- a/drivers/gpu/drm/radeon/radeon_asic.c
+++ b/drivers/gpu/drm/radeon/radeon_asic.c
@@ -1768,6 +1768,7 @@ static struct radeon_asic btc_asic = {
                 .print_power_state = &rv770_dpm_print_power_state,
                 .debugfs_print_current_performance_level = &rv770_dpm_debugfs_print_current_performance_level,
                 .force_performance_level = &rv770_dpm_force_performance_level,
+                .vblank_too_short = &btc_dpm_vblank_too_short,
         },
         .pflip = {
                 .pre_page_flip = &evergreen_pre_page_flip,
diff --git a/drivers/gpu/drm/radeon/radeon_asic.h b/drivers/gpu/drm/radeon/radeon_asic.h
index 0ef8b4967b9c..bca9a8bc062b 100644
--- a/drivers/gpu/drm/radeon/radeon_asic.h
+++ b/drivers/gpu/drm/radeon/radeon_asic.h
@@ -556,6 +556,7 @@ void btc_dpm_post_set_power_state(struct radeon_device *rdev);
 void btc_dpm_fini(struct radeon_device *rdev);
 u32 btc_dpm_get_sclk(struct radeon_device *rdev, bool low);
 u32 btc_dpm_get_mclk(struct radeon_device *rdev, bool low);
+bool btc_dpm_vblank_too_short(struct radeon_device *rdev);
 int sumo_dpm_init(struct radeon_device *rdev);
 int sumo_dpm_enable(struct radeon_device *rdev);
 void sumo_dpm_disable(struct radeon_device *rdev);