[Mesa-dev] [PATCH 04/10] radeonsi/gfx9: fix linear mipmap CPU access

[Marek Olšák]

On Fri, Mar 31, 2017 at 8:17 AM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> On 30.03.2017 19:16, Marek Olšák wrote:
>>
>> From: Marek Olšák <marek.olsak at amd.com>
>>
>> ---
>>  src/gallium/drivers/radeon/r600_texture.c      | 8 +++-----
>>  src/gallium/drivers/radeon/radeon_winsys.h     | 4 ++--
>>  src/gallium/winsys/amdgpu/drm/amdgpu_surface.c | 2 +-
>>  3 files changed, 6 insertions(+), 8 deletions(-)
>>
>> diff --git a/src/gallium/drivers/radeon/r600_texture.c
>> b/src/gallium/drivers/radeon/r600_texture.c
>> index 877f555..77e9bec 100644
>> --- a/src/gallium/drivers/radeon/r600_texture.c
>> +++ b/src/gallium/drivers/radeon/r600_texture.c
>> @@ -186,22 +186,22 @@ static unsigned r600_texture_get_offset(struct
>> r600_common_screen *rscreen,
>>         if (rscreen->chip_class >= GFX9) {
>>                 *stride = rtex->surface.u.gfx9.surf_pitch *
>> rtex->surface.bpe;
>>                 *layer_stride = rtex->surface.u.gfx9.surf_slice_size;
>>
>>                 if (!box)
>>                         return 0;
>>
>>                 /* Each texture is an array of slices. Each slice is an
>> array
>>                  * of mipmap levels. */
>>                 return box->z * rtex->surface.u.gfx9.surf_slice_size +
>> -                      ((rtex->surface.u.gfx9.surf_ymip_offset[level] +
>> -                        box->y / rtex->surface.blk_h) *
>> +                      rtex->surface.u.gfx9.offset[level] +
>> +                      (box->y / rtex->surface.blk_h *
>>                         rtex->surface.u.gfx9.surf_pitch +
>>                         box->x / rtex->surface.blk_w) * rtex->surface.bpe;
>
>
> Does this part of the formula really not depend on the mip level? It looks
> like each mip level uses the same amount of memory and pitch?

Only the same pitch. All mip levels are placed in one 2D plane. The
linear layout puts them below each other. That's why the pitch is the
same. blk_w/blk_h are for compressed textures.

Marek