drm/nouveau/mxm: initial implementation of dcb sanitisation

The DCB table provided by the VBIOS on most MXM chips has a number of
entries which either need to be disabled, or modified according to the
MXM-SIS Output Device Descriptors.

The x86 vbios code usually takes care of this for us, however, with the
large number of laptops now with switchable graphics or optimus, a lot
of the time nouveau is responsible for POSTing the card instead - leaving
some fun situations like, plugging in a monitor and having nouveau decide
3 connectors actually just got plugged in..

No MXM-SIS fetching methods implemented yet.

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

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_bios.c b/drivers/gpu/drm/nouveau/nouveau_bios.c
index 35b18f4f7c4e..1faa7d9ceb94 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bios.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bios.c
@@ -5382,6 +5382,9 @@ bit_table(struct drm_device *dev, u8 id, struct bit_entry *bit)
         struct nvbios *bios = &dev_priv->vbios;
         u8 entries, *entry;
 
+        if (bios->type != NVBIOS_BIT)
+                return -ENODEV;
+
         entries = bios->data[bios->offset + 10];
         entry   = &bios->data[bios->offset + 12];
         while (entries--) {
@@ -5832,7 +5835,7 @@ dcb_table(struct drm_device *dev)
         return NULL;
 }
 
-u8 *
+void *
 dcb_outp(struct drm_device *dev, u8 idx)
 {
         u8 *dcb = dcb_table(dev);
@@ -6663,6 +6666,10 @@ nouveau_bios_init(struct drm_device *dev)
         if (ret)
                 return ret;
 
+        ret = nouveau_mxm_init(dev);
+        if (ret)
+                return ret;
+
         ret = parse_dcb_table(dev, bios);
         if (ret)
                 return ret;
@@ -6703,5 +6710,6 @@ nouveau_bios_init(struct drm_device *dev)
 void
 nouveau_bios_takedown(struct drm_device *dev)
 {
+        nouveau_mxm_fini(dev);
         nouveau_i2c_fini(dev);
 }