From d1084184789d677df4e9c110f38cb3f3d709195d Mon Sep 17 00:00:00 2001
From: Ben Skeggs <bskeggs@redhat.com>
Date: Wed, 29 May 2019 09:58:18 +1000
Subject: [PATCH] drm/nouveau/kms: disallow dual-link harder if hdmi connection
detected
The fallthrough cases (pre-Fermi) would accidentally allow dual-link pixel
clocks even where they shouldn't be. This leads to a high resolution HDMI
displays, connected via a DVI->HDMI adapter, to fail on the original NV50.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
---
drivers/gpu/drm/nouveau/nouveau_connector.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 4116ee62adafe..caa8c75958899 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -978,11 +978,13 @@ get_tmds_link_bandwidth(struct drm_connector *connector)
struct nouveau_drm *drm = nouveau_drm(connector->dev);
struct dcb_output *dcb = nv_connector->detected_encoder->dcb;
struct drm_display_info *info = NULL;
- const unsigned duallink_scale =
+ unsigned duallink_scale =
nouveau_duallink && nv_encoder->dcb->duallink_possible ? 2 : 1;
- if (drm_detect_hdmi_monitor(nv_connector->edid))
+ if (drm_detect_hdmi_monitor(nv_connector->edid)) {
info = &nv_connector->base.display_info;
+ duallink_scale = 1;
+ }
if (info) {
if (nouveau_hdmimhz > 0)
@@ -1003,6 +1005,7 @@ get_tmds_link_bandwidth(struct drm_connector *connector)
if (drm->client.device.info.family >= NV_DEVICE_INFO_V0_FERMI)
return 225000;
}
+
if (dcb->location != DCB_LOC_ON_CHIP ||
drm->client.device.info.chipset >= 0x46)
return 165000 * duallink_scale;
--
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