[RESEND PATCH] drm/nouveau: fix init with agpgart-uninorth

[Marcin Slusarz]

On Mon, Dec 31, 2012 at 03:34:59AM +0200, Aaro Koskinen wrote:
> Check that the AGP aperture can be mapped. This follows a similar change
> done for Radeon (commit 365048ff, drm/radeon: AGP memory is only I/O if
> the aperture can be mapped by the CPU.).
> 
> The patch fixes the following error seen on G5 iMac:
> 
> 	nouveau E[     DRM] failed to create kernel channel, -12
> 
> Reviewed-by: Michel Dänzer <michel at daenzer.net>
> Signed-off-by: Aaro Koskinen <aaro.koskinen at iki.fi>
> ---

This patch fixes https://bugs.freedesktop.org/show_bug.cgi?id=58806.
For some (weird) reason Nouveau worked on this configuration on 3.6 kernel,
so cc'ing stable at vger seems to be appropriate.

>  drivers/gpu/drm/nouveau/nouveau_bo.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
> index 5614c89..69d7b1d 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_bo.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
> @@ -1276,7 +1276,7 @@ nouveau_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
>  		if (drm->agp.stat == ENABLED) {
>  			mem->bus.offset = mem->start << PAGE_SHIFT;
>  			mem->bus.base = drm->agp.base;
> -			mem->bus.is_iomem = true;
> +			mem->bus.is_iomem = !dev->agp->cant_use_aperture;
>  		}
>  #endif
>  		break;
> --