Re: [PATCH v2 1/2] drm/amd/display: fix the white screen issue when >= 64GB DRAM

[Christian König <ckoenig.leichtzumerken@xxxxxxxxx>]

Am 08.09.23 um 16:55 schrieb Hamza Mahfooz:
> From: Yifan Zhang <yifan1.zhang@xxxxxxx>
>
> Dropping bit 31:4 of page table base is wrong, it makes page table
> base points to wrong address if phys addr is beyond 64GB; dropping
> page_table_start/end bit 31:4 is unnecessary since dcn20_vmid_setup
> will do that. Also, while we are at it, cleanup the assignments using
> upper_32_bits()/lower_32_bits() and AMDGPU_GPU_PAGE_SHIFT.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2354
> Fixes: 81d0bcf99009 ("drm/amdgpu: make display pinning more flexible (v2)")
> Signed-off-by: Yifan Zhang <yifan1.zhang@xxxxxxx>
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>

Reviewed-by: Christian König <christian.koenig@xxxxxxx> for the series 
as well.

> ---
> v2: use upper_32_bits()/lower_32_bits() and AMDGPU_GPU_PAGE_SHIFT
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 14 +++++++++-----
>   1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 1bb1a394f55f..5f14cd9391ca 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1283,11 +1283,15 @@ static void mmhub_read_system_context(struct amdgpu_device *adev, struct dc_phy_
>   
>   	pt_base = amdgpu_gmc_pd_addr(adev->gart.bo);
>   
> -	page_table_start.high_part = (u32)(adev->gmc.gart_start >> 44) & 0xF;
> -	page_table_start.low_part = (u32)(adev->gmc.gart_start >> 12);
> -	page_table_end.high_part = (u32)(adev->gmc.gart_end >> 44) & 0xF;
> -	page_table_end.low_part = (u32)(adev->gmc.gart_end >> 12);
> -	page_table_base.high_part = upper_32_bits(pt_base) & 0xF;
> +	page_table_start.high_part = upper_32_bits(adev->gmc.gart_start >>
> +						   AMDGPU_GPU_PAGE_SHIFT);
> +	page_table_start.low_part = lower_32_bits(adev->gmc.gart_start >>
> +						  AMDGPU_GPU_PAGE_SHIFT);
> +	page_table_end.high_part = upper_32_bits(adev->gmc.gart_end >>
> +						 AMDGPU_GPU_PAGE_SHIFT);
> +	page_table_end.low_part = lower_32_bits(adev->gmc.gart_end >>
> +						AMDGPU_GPU_PAGE_SHIFT);
> +	page_table_base.high_part = upper_32_bits(pt_base);
>   	page_table_base.low_part = lower_32_bits(pt_base);
>   
>   	pa_config->system_aperture.start_addr = (uint64_t)logical_addr_low << 18;