[PATCH] drm/amdgpu: adjust gtt memory size

[Christian König]

Am 21.07.2016 um 09:46 schrieb Ken Wang:
> Change-Id: If00d5b97ba9e30f9b7f68fdfc134a0f8b3ad2add
> Signed-off-by: Ken Wang <Qingqing.Wang at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 7 ++++++-
>   drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 7 ++++++-
>   2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> index a3b6048..0b095d5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> @@ -336,6 +336,11 @@ static int gmc_v7_0_mc_init(struct amdgpu_device *adev)
>   {
>   	u32 tmp;
>   	int chansize, numchan;
> +	u64 sysmem_size;
> +	struct sysinfo si;
> +
> +	si_meminfo(&si);
> +	sysmem_size = si.totalram * si.mem_unit;

This doesn't work on 32bit systems since totalram is a long (IIRC) and 
so this will certainly overflow.

Additional if I remember correctly we didn't ended the discussion on 
what to do here with a conclusion.

Regards,
Christian.

>   
>   	/* Get VRAM informations */
>   	tmp = RREG32(mmMC_ARB_RAMCFG);
> @@ -392,7 +397,7 @@ static int gmc_v7_0_mc_init(struct amdgpu_device *adev)
>   	 * size equal to the 1024 or vram, whichever is larger.
>   	 */
>   	if (amdgpu_gart_size == -1)
> -		adev->mc.gtt_size = max((1024ULL << 20), adev->mc.mc_vram_size);
> +		adev->mc.gtt_size = max((1024ULL << 20), min(adev->mc.mc_vram_size, sysmem_size/2));
>   	else
>   		adev->mc.gtt_size = (uint64_t)amdgpu_gart_size << 20;
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> index 02b6872..790bf7a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> @@ -413,6 +413,11 @@ static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
>   {
>   	u32 tmp;
>   	int chansize, numchan;
> +	u64 sysmem_size;
> +	struct sysinfo si;
> +
> +	si_meminfo(&si);
> +	sysmem_size = si.totalram * si.mem_unit;
>   
>   	/* Get VRAM informations */
>   	tmp = RREG32(mmMC_ARB_RAMCFG);
> @@ -469,7 +474,7 @@ static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
>   	 * size equal to the 1024 or vram, whichever is larger.
>   	 */
>   	if (amdgpu_gart_size == -1)
> -		adev->mc.gtt_size = max((1024ULL << 20), adev->mc.mc_vram_size);
> +		adev->mc.gtt_size = max((1024ULL << 20), min(adev->mc.mc_vram_size, sysmem_size/2));
>   	else
>   		adev->mc.gtt_size = (uint64_t)amdgpu_gart_size << 20;
>