drm/nv50: prevent accidently turning off encoders we're actually using

On most cards the DisplayPort connector is created with 2 encoders sharing
a single SOR (for native DP, and for DVI-over-DP).  The previous logic
for turning off unused encoders didn't take into account that we could
have multiple drm_encoders on a single hw encoder and ended up turning off
encoders that were actually being used still.

This patch fixes that issue.  We probably want to look at something a bit
better later on, and only expose one drm_encoder per hw encoder block.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 21 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/nv50_crtc.c b/drivers/gpu/drm/nouveau/nv50_crtc.c
index 118d3285fd8c..40b7360841f8 100644
--- a/drivers/gpu/drm/nouveau/nv50_crtc.c
+++ b/drivers/gpu/drm/nouveau/nv50_crtc.c
@@ -432,6 +432,7 @@ nv50_crtc_prepare(struct drm_crtc *crtc)
         struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
         struct drm_device *dev = crtc->dev;
         struct drm_encoder *encoder;
+        uint32_t dac = 0, sor = 0;
 
         NV_DEBUG_KMS(dev, "index %d\n", nv_crtc->index);
 
@@ -439,9 +440,28 @@ nv50_crtc_prepare(struct drm_crtc *crtc)
         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
                 struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
 
-                if (drm_helper_encoder_in_use(encoder))
+                if (!drm_helper_encoder_in_use(encoder))
                         continue;
 
+                if (nv_encoder->dcb->type == OUTPUT_ANALOG ||
+                    nv_encoder->dcb->type == OUTPUT_TV)
+                        dac |= (1 << nv_encoder->or);
+                else
+                        sor |= (1 << nv_encoder->or);
+        }
+
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+                struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
+
+                if (nv_encoder->dcb->type == OUTPUT_ANALOG ||
+                    nv_encoder->dcb->type == OUTPUT_TV) {
+                        if (dac & (1 << nv_encoder->or))
+                                continue;
+                } else {
+                        if (sor & (1 << nv_encoder->or))
+                                continue;
+                }
+
                 nv_encoder->disconnect(nv_encoder);
         }