drm/radeon: properly handle crtc powergating

Need to make sure the crtc is gated on before modesetting.
Explicitly gate the crtc on in prepare() and set a flag
so that the dpms functions don't gate it off during
mode set.

Noticed by sylware on IRC.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 9e6f76fec527..dc279ebf7afb 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -259,7 +259,7 @@ void atombios_crtc_dpms(struct drm_crtc *crtc, int mode)
                 /* adjust pm to dpms changes BEFORE enabling crtcs */
                 radeon_pm_compute_clocks(rdev);
                 /* disable crtc pair power gating before programming */
-                if (ASIC_IS_DCE6(rdev))
+                if (ASIC_IS_DCE6(rdev) && !radeon_crtc->in_mode_set)
                         atombios_powergate_crtc(crtc, ATOM_DISABLE);
                 atombios_enable_crtc(crtc, ATOM_ENABLE);
                 if (ASIC_IS_DCE3(rdev) && !ASIC_IS_DCE6(rdev))
@@ -279,7 +279,7 @@ void atombios_crtc_dpms(struct drm_crtc *crtc, int mode)
                 atombios_enable_crtc(crtc, ATOM_DISABLE);
                 radeon_crtc->enabled = false;
                 /* power gating is per-pair */
-                if (ASIC_IS_DCE6(rdev)) {
+                if (ASIC_IS_DCE6(rdev) && !radeon_crtc->in_mode_set) {
                         struct drm_crtc *other_crtc;
                         struct radeon_crtc *other_radeon_crtc;
                         list_for_each_entry(other_crtc, &rdev->ddev->mode_config.crtc_list, head) {
@@ -1635,18 +1635,28 @@ static bool atombios_crtc_mode_fixup(struct drm_crtc *crtc,
 static void atombios_crtc_prepare(struct drm_crtc *crtc)
 {
         struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
+        struct drm_device *dev = crtc->dev;
+        struct radeon_device *rdev = dev->dev_private;
 
+        radeon_crtc->in_mode_set = true;
         /* pick pll */
         radeon_crtc->pll_id = radeon_atom_pick_pll(crtc);
 
+        /* disable crtc pair power gating before programming */
+        if (ASIC_IS_DCE6(rdev))
+                atombios_powergate_crtc(crtc, ATOM_DISABLE);
+
         atombios_lock_crtc(crtc, ATOM_ENABLE);
         atombios_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
 }
 
 static void atombios_crtc_commit(struct drm_crtc *crtc)
 {
+        struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
+
         atombios_crtc_dpms(crtc, DRM_MODE_DPMS_ON);
         atombios_lock_crtc(crtc, ATOM_DISABLE);
+        radeon_crtc->in_mode_set = false;
 }
 
 static void atombios_crtc_disable(struct drm_crtc *crtc)