[PATCH 01/10] drm/amdgpu: use only the lower address space on GMC9

[Zhang, Jerry (Junwei)]

On 08/28/2018 12:53 AM, Christian König wrote:
> Only use the lower address space on GMC9 for the system domain.
> Otherwise we would need to sign extend GMC addresses.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> index e44b5191735d..d982956c8329 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> @@ -938,11 +938,10 @@ static int gmc_v9_0_sw_init(void *handle)
>   	if (r)
>   		return r;
>
> -	/* Set the internal MC address mask
> -	 * This is the max address of the GPU's
> -	 * internal address space.
> +	/* Use only the lower range for the internal MC address mask. This is
> +	 * the max address of the GPU's internal address space.
>   	 */
> -	adev->gmc.mc_mask = 0xffffffffffffULL; /* 48 bit MC */
> +	adev->gmc.mc_mask = 0x7fffffffffffULL;

do we need to update vm_size as 128T at the same time?

Jerry

>
>   	/* set DMA mask + need_dma32 flags.
>   	 * PCIE - can handle 44-bits.
>