drm/nouveau/fbcon: using nv_two_heads is not a good idea
authorBen Skeggs <bskeggs@redhat.com>
Tue, 26 Jun 2012 02:12:30 +0000 (12:12 +1000)
committerDave Airlie <airlied@redhat.com>
Tue, 26 Jun 2012 11:16:43 +0000 (12:16 +0100)
nv_two_heads() was never meant to be used outside of pre-nv50 code.  The
code checks for >= NV_10 for 2 CRTCs, then downgrades a few specific
chipsets to 1 CRTC based on (pci_device & 0x0ff0).

The breakage example seen is on GTX 560Ti, with a pciid of 0x1200, which
gets detected as an NV20 (0x020x) with 1 CRTC by nv_two_heads(), causing
memory corruption because there's actually 2 CRTCs..

This switches fbcon to use the CRTC count directly from the mode_config
structure, which will also fix the same issue on Kepler boards which have
4 CRTCs.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
drivers/gpu/drm/nouveau/nouveau_fbcon.c

index 153b9a1..1074bc5 100644 (file)
@@ -467,7 +467,7 @@ int nouveau_fbcon_init(struct drm_device *dev)
        nfbdev->helper.funcs = &nouveau_fbcon_helper_funcs;
 
        ret = drm_fb_helper_init(dev, &nfbdev->helper,
-                                nv_two_heads(dev) ? 2 : 1, 4);
+                                dev->mode_config.num_crtc, 4);
        if (ret) {
                kfree(nfbdev);
                return ret;