[RFC PATCH 1/1] drm/amdgpu: fix usable gart size calculation

[Nirmoy]

On 11/13/20 5:21 PM, Christian König wrote:
> Am 13.11.20 um 17:17 schrieb Nirmoy Das:
>> amdgpu_do_test_moves() is failing because of wrong
>> usable gart size calculation and throwing:
>>
>> [drm:amdgpu_do_test_moves [amdgpu]] *ERROR* 0000000020bdc9f3 bind failed
>>
>> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
>> ---
>>
>> This still doesn't work. As per my calculation 1st 4MB of GART is not
>> accounted for in adev->gmc.gart_size - 
>> atomic64_read(&adev->gart_pin_size).
>
> The member gart_pin_size should probably be renamed to gtt_pin_size, 
> but since a gtt pin is also automatically visible in the GART that 
> should probably be ok for now.
>
>> What am I missing ?
>
> The two 2MB windows in the GART which are used for buffer moves.
>
> See AMDGPU_GTT_MAX_TRANSFER_SIZE and AMDGPU_GTT_NUM_TRANSFER_WINDOWS.


Thanks, I should've asked much earlier :)


Nirmoy

>
> Regards,
> Christian.
>
>>
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_test.c | 11 ++---------
>>   1 file changed, 2 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_test.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_test.c
>> index 6042b3b81a4c..d983c729997f 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_test.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_test.c
>> @@ -42,16 +42,9 @@ static void amdgpu_do_test_moves(struct 
>> amdgpu_device *adev)
>>       size = 1024 * 1024;
>>
>>       /* Number of tests =
>> -     * (Total GTT - IB pool - writeback page - ring buffers) / test 
>> size
>> +     * (Total GTT - gart_pin_size) / test size
>>        */
>> -    n = adev->gmc.gart_size - AMDGPU_IB_POOL_SIZE;
>> -    for (i = 0; i < AMDGPU_MAX_RINGS; ++i)
>> -        if (adev->rings[i])
>> -            n -= adev->rings[i]->ring_size;
>> -    if (adev->wb.wb_obj)
>> -        n -= AMDGPU_GPU_PAGE_SIZE;
>> -    if (adev->irq.ih.ring_obj)
>> -        n -= adev->irq.ih.ring_size;
>> +    n = adev->gmc.gart_size - atomic64_read(&adev->gart_pin_size);
>>       n /= size;
>>
>>       gtt_obj = kcalloc(n, sizeof(*gtt_obj), GFP_KERNEL);
>> -- 
>> 2.29.0
>>
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx at lists.freedesktop.org
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&data=04%7C01%7Cnirmoy.das%40amd.com%7Cc9c61fcfe5b744b494c208d887f0430e%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637408813271687888%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=o9w4aKiHNAZvkcWPHTiZQZC5nrOYdjs7TqMpZ3d8AJ0%3D&reserved=0 
>>
>