drm/nouveau/disp: activate dual link TMDS links only when possible

Without this patch a pixel clock rate above 165 MHz on a TMDS link is
assumed to be dual link. This is true for DVI, but not for HDMI. HDMI
supports no dual link, but it supports pixel clock rates above 165 MHz.
Only activate Dual Link mode when it is actually possible and requested.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
[imirkin: check for hdmi monitor for computing proto, use sor ctrl to
 enable extra config bit]
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
index 44e1952582aa3c81eaf4178047de3165788863d0..ee97eae3c973a7025e55fa7b6b78ab96ad8078e1 100644 (file)
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -1962,10 +1962,17 @@ nv50_sor_mode_set(struct drm_encoder *encoder, struct drm_display_mode *umode,
        switch (nv_encoder->dcb->type) {
        case DCB_OUTPUT_TMDS:
                if (nv_encoder->dcb->sorconf.link & 1) {
-                       if (mode->clock < 165000)
-                               proto = 0x1;
-                       else
-                               proto = 0x5;
+                       proto = 0x1;
+                       /* Only enable dual-link if:
+                        *  - Need to (i.e. rate > 165MHz)
+                        *  - DCB says we can
+                        *  - Not an HDMI monitor, since there's no dual-link
+                        *    on HDMI.
+                        */
+                       if (mode->clock >= 165000 &&
+                           nv_encoder->dcb->duallink_possible &&
+                           !drm_detect_hdmi_monitor(nv_connector->edid))
+                               proto |= 0x4;
                } else {
                        proto = 0x2;
                }

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/gf119.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/gf119.c
index 186fd3ac78f6cb9cfc47fe0783382ce12eb38cdc..f0314664349c3b2c39ef650e1ecdc636bde5aae1 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/gf119.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/gf119.c
@@ -158,7 +158,7 @@ exec_clkcmp(struct nv50_disp *disp, int head, int id, u32 pclk, u32 *conf)
        switch (outp->info.type) {
        case DCB_OUTPUT_TMDS:
                *conf = (ctrl & 0x00000f00) >> 8;
-               if (pclk >= 165000)
+               if (*conf == 5)
                        *conf |= 0x0100;
                break;
        case DCB_OUTPUT_LVDS:

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c
index 32e73a975b587721df70c2135276b51a4c74d1ed..4226d2153b9c2a1f8072697fbb77c1b7838e9e09 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c
@@ -391,7 +391,7 @@ exec_clkcmp(struct nv50_disp *disp, int head, int id, u32 pclk, u32 *conf)
                switch (outp->info.type) {
                case DCB_OUTPUT_TMDS:
                        *conf = (ctrl & 0x00000f00) >> 8;
-                       if (pclk >= 165000)
+                       if (*conf == 5)
                                *conf |= 0x0100;
                        break;
                case DCB_OUTPUT_LVDS: