drm/nouveau/dp: fix required link bandwidth calculations

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

diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c b/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
index 26e962b7e702a07fabf713cbcd2ca00ac6527ae5..2283c442a10d48e06761720e5ff7100fa9b74e4a 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
@@ -1516,11 +1516,11 @@ nv50_disp_intr_unk20_2(struct nv50_disp_priv *priv, int head)
                }
 
                switch ((ctrl & 0x000f0000) >> 16) {
-               case 6: datarate = pclk * 30 / 8; break;
-               case 5: datarate = pclk * 24 / 8; break;
+               case 6: datarate = pclk * 30; break;
+               case 5: datarate = pclk * 24; break;
                case 2:
                default:
-                       datarate = pclk * 18 / 8;
+                       datarate = pclk * 18;
                        break;
                }
 

diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c b/drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c
index 48aa38a87e3fdb9651aea5f99586cf380099335f..fa30d8196f35928cf2c98d17b6f8ab6a0809cfe5 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/nvd0.c
@@ -1159,11 +1159,11 @@ nvd0_disp_intr_unk2_2(struct nv50_disp_priv *priv, int head)
        if (outp->info.type == DCB_OUTPUT_DP) {
                u32 sync = nv_rd32(priv, 0x660404 + (head * 0x300));
                switch ((sync & 0x000003c0) >> 6) {
-               case 6: pclk = pclk * 30 / 8; break;
-               case 5: pclk = pclk * 24 / 8; break;
+               case 6: pclk = pclk * 30; break;
+               case 5: pclk = pclk * 24; break;
                case 2:
                default:
-                       pclk = pclk * 18 / 8;
+                       pclk = pclk * 18;
                        break;
                }
 

diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/outpdp.c b/drivers/gpu/drm/nouveau/core/engine/disp/outpdp.c
index 52c299c3d3008eed897aec9aec7943e5c23e1454..eb2d7789555d420505849c447b6d20a2972eb891 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/engine/disp/outpdp.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/outpdp.c
@@ -34,7 +34,7 @@ nvkm_output_dp_train(struct nvkm_output *base, u32 datarate, bool wait)
        struct nvkm_output_dp *outp = (void *)base;
        bool retrain = true;
        u8 link[2], stat[3];
-       u32 rate;
+       u32 linkrate;
        int ret, i;
 
        /* check that the link is trained at a high enough rate */
@@ -44,8 +44,10 @@ nvkm_output_dp_train(struct nvkm_output *base, u32 datarate, bool wait)
                goto done;
        }
 
-       rate = link[0] * 27000 * (link[1] & DPCD_LC01_LANE_COUNT_SET);
-       if (rate < ((datarate / 8) * 10)) {
+       linkrate = link[0] * 27000 * (link[1] & DPCD_LC01_LANE_COUNT_SET);
+       linkrate = (linkrate * 8) / 10; /* 8B/10B coding overhead */
+       datarate = (datarate + 9) / 10; /* -> decakilobits */
+       if (linkrate < datarate) {
                DBG("link not trained at sufficient rate\n");
                goto done;
        }