[PATCH] drm/amdgpu: consider user preference when pinning for SG display

[PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Alex Deucher]

If the pin domain is set to GTT | VRAM, look at the preferred domains
for the bo and respect that if it's been set explicitly.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 6a9e46ae7f0a..16192f17653e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
 	 * See function amdgpu_display_supported_domains()
 	 */
 	if (domain == (AMDGPU_GEM_DOMAIN_VRAM | AMDGPU_GEM_DOMAIN_GTT)) {
-		domain = AMDGPU_GEM_DOMAIN_VRAM;
-		if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
+		if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
+			domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user really wants vram, respect it */
+		else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
+			domain = AMDGPU_GEM_DOMAIN_GTT; /* if user really wants gtt, respect it */
+		else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
 			domain = AMDGPU_GEM_DOMAIN_GTT;
+		else
+			domain = AMDGPU_GEM_DOMAIN_VRAM;
 	}
 
 	if (bo->pin_count) {
-- 
2.13.6

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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Michel Dänzer]

On 2018-05-17 06:55 PM, Alex Deucher wrote:
> If the pin domain is set to GTT | VRAM, look at the preferred domains
> for the bo and respect that if it's been set explicitly.
> 
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 6a9e46ae7f0a..16192f17653e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
>  	 * See function amdgpu_display_supported_domains()
>  	 */
>  	if (domain == (AMDGPU_GEM_DOMAIN_VRAM | AMDGPU_GEM_DOMAIN_GTT)) {
> -		domain = AMDGPU_GEM_DOMAIN_VRAM;
> -		if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
> +		if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
> +			domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user really wants vram, respect it */
> +		else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
> +			domain = AMDGPU_GEM_DOMAIN_GTT; /* if user really wants gtt, respect it */

I'd spell VRAM and GTT in capital letters in the comments.


> +		else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>  			domain = AMDGPU_GEM_DOMAIN_GTT;
> +		else
> +			domain = AMDGPU_GEM_DOMAIN_VRAM;
>  	}

Is everything in place to deal with any issues that might occur when
flipping between buffers in VRAM and GTT?


-- 
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Libre software enthusiast             |             Mesa and X developer
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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Christian König]

Am 17.05.2018 um 18:55 schrieb Alex Deucher:
> If the pin domain is set to GTT | VRAM, look at the preferred domains
> for the bo and respect that if it's been set explicitly.
>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 6a9e46ae7f0a..16192f17653e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
>   	 * See function amdgpu_display_supported_domains()
>   	 */
>   	if (domain == (AMDGPU_GEM_DOMAIN_VRAM | AMDGPU_GEM_DOMAIN_GTT)) {
> -		domain = AMDGPU_GEM_DOMAIN_VRAM;
> -		if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
> +		if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
> +			domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user really wants vram, respect it */
> +		else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
> +			domain = AMDGPU_GEM_DOMAIN_GTT; /* if user really wants gtt, respect it */
> +		else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>   			domain = AMDGPU_GEM_DOMAIN_GTT;
> +		else
> +			domain = AMDGPU_GEM_DOMAIN_VRAM;
>   	}
>   
>   	if (bo->pin_count) {

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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Samuel Li]

On 2018-05-18 04:21 AM, Michel Dänzer wrote:
> On 2018-05-17 06:55 PM, Alex Deucher wrote:
>> If the pin domain is set to GTT | VRAM, look at the preferred domains
>> for the bo and respect that if it's been set explicitly.
>>
>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> index 6a9e46ae7f0a..16192f17653e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
>>  	 * See function amdgpu_display_supported_domains()
>>  	 */
>>  	if (domain == (AMDGPU_GEM_DOMAIN_VRAM | AMDGPU_GEM_DOMAIN_GTT)) {
>> -		domain = AMDGPU_GEM_DOMAIN_VRAM;
>> -		if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>> +		if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
>> +			domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user really wants vram, respect it */
>> +		else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
>> +			domain = AMDGPU_GEM_DOMAIN_GTT; /* if user really wants gtt, respect it */
> 
> I'd spell VRAM and GTT in capital letters in the comments.
> 
> 
>> +		else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>  			domain = AMDGPU_GEM_DOMAIN_GTT;
>> +		else
>> +			domain = AMDGPU_GEM_DOMAIN_VRAM;
>>  	}
> 
> Is everything in place to deal with any issues that might occur when
> flipping between buffers in VRAM and GTT?
> 
Besides this question, I am also wondering how to deal with the first display buffer created in kernel at amdgpufb_create_pinned_object()?

Sam


> 
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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Alex Deucher]

On Fri, May 18, 2018 at 4:21 AM, Michel Dänzer <michel@daenzer.net> wrote:
> On 2018-05-17 06:55 PM, Alex Deucher wrote:
>> If the pin domain is set to GTT | VRAM, look at the preferred domains
>> for the bo and respect that if it's been set explicitly.
>>
>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> index 6a9e46ae7f0a..16192f17653e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
>>        * See function amdgpu_display_supported_domains()
>>        */
>>       if (domain == (AMDGPU_GEM_DOMAIN_VRAM | AMDGPU_GEM_DOMAIN_GTT)) {
>> -             domain = AMDGPU_GEM_DOMAIN_VRAM;
>> -             if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>> +             if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
>> +                     domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user really wants vram, respect it */
>> +             else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
>> +                     domain = AMDGPU_GEM_DOMAIN_GTT; /* if user really wants gtt, respect it */
>
> I'd spell VRAM and GTT in capital letters in the comments.

OK.

>
>
>> +             else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>                       domain = AMDGPU_GEM_DOMAIN_GTT;
>> +             else
>> +                     domain = AMDGPU_GEM_DOMAIN_VRAM;
>>       }
>
> Is everything in place to deal with any issues that might occur when
> flipping between buffers in VRAM and GTT?
>

Ah, right, I forgot about that, we still need to do that.  In practice
I don't think this will change anything compared things now at least
the way mesa is currently configured.  I can hold off on this this
patch for now until we handle that if you think it will be an issue.

Alex
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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Alex Deucher]

On Fri, May 18, 2018 at 2:22 PM, Samuel Li <samuel.li@amd.com> wrote:
>
>
> On 2018-05-18 04:21 AM, Michel Dänzer wrote:
>> On 2018-05-17 06:55 PM, Alex Deucher wrote:
>>> If the pin domain is set to GTT | VRAM, look at the preferred domains
>>> for the bo and respect that if it's been set explicitly.
>>>
>>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>>> ---
>>>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>> index 6a9e46ae7f0a..16192f17653e 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
>>>       * See function amdgpu_display_supported_domains()
>>>       */
>>>      if (domain == (AMDGPU_GEM_DOMAIN_VRAM | AMDGPU_GEM_DOMAIN_GTT)) {
>>> -            domain = AMDGPU_GEM_DOMAIN_VRAM;
>>> -            if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>> +            if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user really wants vram, respect it */
>>> +            else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
>>> +                    domain = AMDGPU_GEM_DOMAIN_GTT; /* if user really wants gtt, respect it */
>>
>> I'd spell VRAM and GTT in capital letters in the comments.
>>
>>
>>> +            else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>                      domain = AMDGPU_GEM_DOMAIN_GTT;
>>> +            else
>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>      }
>>
>> Is everything in place to deal with any issues that might occur when
>> flipping between buffers in VRAM and GTT?
>>
> Besides this question, I am also wondering how to deal with the first display buffer created in kernel at amdgpufb_create_pinned_object()?

amdgpufb_create_pinned_object() calls
amdgpu_display_supported_domains() for the initial domain and
amdgpu_gem_object_create() uses that for the preferred domain so it
won't change the behavior there.

Alex
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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Christian König]

Am 18.05.2018 um 21:16 schrieb Alex Deucher:
> On Fri, May 18, 2018 at 2:22 PM, Samuel Li <samuel.li@amd.com> wrote:
>>
>> On 2018-05-18 04:21 AM, Michel Dänzer wrote:
>>> On 2018-05-17 06:55 PM, Alex Deucher wrote:
>>>> If the pin domain is set to GTT | VRAM, look at the preferred domains
>>>> for the bo and respect that if it's been set explicitly.
>>>>
>>>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>>>> ---
>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>>>>   1 file changed, 7 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>> index 6a9e46ae7f0a..16192f17653e 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
>>>>        * See function amdgpu_display_supported_domains()
>>>>        */
>>>>       if (domain == (AMDGPU_GEM_DOMAIN_VRAM | AMDGPU_GEM_DOMAIN_GTT)) {
>>>> -            domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>> -            if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>> +            if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user really wants vram, respect it */
>>>> +            else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
>>>> +                    domain = AMDGPU_GEM_DOMAIN_GTT; /* if user really wants gtt, respect it */
>>> I'd spell VRAM and GTT in capital letters in the comments.
>>>
>>>
>>>> +            else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>>                       domain = AMDGPU_GEM_DOMAIN_GTT;
>>>> +            else
>>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>>       }
>>> Is everything in place to deal with any issues that might occur when
>>> flipping between buffers in VRAM and GTT?
>>>
>> Besides this question, I am also wondering how to deal with the first display buffer created in kernel at amdgpufb_create_pinned_object()?
> amdgpufb_create_pinned_object() calls
> amdgpu_display_supported_domains() for the initial domain and
> amdgpu_gem_object_create() uses that for the preferred domain so it
> won't change the behavior there.

That was actually something I was not sure about when I initially 
created the patch.

See the FB emulation expects some pointer into a linear PCI resource 
(VRAM), I'm not sure if that can actually deal with something kmapped 
into the vmap (GTT).

Since this is seldom used and only with low resolution it might be 
better to do the conservative approach and use VRAM here.

And we do a full mode set when switching away from FB emulation AFAIK, 
so the move from VRAM to GTT shouldn't be a problem.

Christian.

>
> Alex
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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Michel Dänzer]

On 2018-05-19 05:59 PM, Christian König wrote:
> Am 18.05.2018 um 21:16 schrieb Alex Deucher:
>> On Fri, May 18, 2018 at 2:22 PM, Samuel Li <samuel.li@amd.com> wrote:
>>>
>>> On 2018-05-18 04:21 AM, Michel Dänzer wrote:
>>>> On 2018-05-17 06:55 PM, Alex Deucher wrote:
>>>>> If the pin domain is set to GTT | VRAM, look at the preferred domains
>>>>> for the bo and respect that if it's been set explicitly.
>>>>>
>>>>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>>>>> ---
>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>>>>>   1 file changed, 7 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>> index 6a9e46ae7f0a..16192f17653e 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo
>>>>> *bo, u32 domain,
>>>>>        * See function amdgpu_display_supported_domains()
>>>>>        */
>>>>>       if (domain == (AMDGPU_GEM_DOMAIN_VRAM |
>>>>> AMDGPU_GEM_DOMAIN_GTT)) {
>>>>> -            domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>>> -            if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>>> +            if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user
>>>>> really wants vram, respect it */
>>>>> +            else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
>>>>> +                    domain = AMDGPU_GEM_DOMAIN_GTT; /* if user
>>>>> really wants gtt, respect it */
>>>> I'd spell VRAM and GTT in capital letters in the comments.
>>>>
>>>>
>>>>> +            else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>>>                       domain = AMDGPU_GEM_DOMAIN_GTT;
>>>>> +            else
>>>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>>>       }
>>>> Is everything in place to deal with any issues that might occur when
>>>> flipping between buffers in VRAM and GTT?
>>>>
>>> Besides this question, I am also wondering how to deal with the first
>>> display buffer created in kernel at amdgpufb_create_pinned_object()?
>> amdgpufb_create_pinned_object() calls
>> amdgpu_display_supported_domains() for the initial domain and
>> amdgpu_gem_object_create() uses that for the preferred domain so it
>> won't change the behavior there.
> 
> That was actually something I was not sure about when I initially
> created the patch.
> 
> See the FB emulation expects some pointer into a linear PCI resource
> (VRAM), I'm not sure if that can actually deal with something kmapped
> into the vmap (GTT).
> 
> Since this is seldom used and only with low resolution

It's not that low resolution these days (normally the smallest native
resolution of all connected displays, i.e. generally >= 1920x1080), i.e.
on the order of ~10 MB of VRAM that can't be used for anything else.

> it might be better to do the conservative approach and use VRAM here.

Or somebody could try forcing GTT for this, and see what happens. :) If
it works, I'd say GTT is actually preferable for this.


> And we do a full mode set when switching away from FB emulation AFAIK,
> so the move from VRAM to GTT shouldn't be a problem.

Agreed.


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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Christian König]

Am 22.05.2018 um 09:22 schrieb Michel Dänzer:
> On 2018-05-19 05:59 PM, Christian König wrote:
>> Am 18.05.2018 um 21:16 schrieb Alex Deucher:
>>> On Fri, May 18, 2018 at 2:22 PM, Samuel Li <samuel.li@amd.com> wrote:
>>>> On 2018-05-18 04:21 AM, Michel Dänzer wrote:
>>>>> On 2018-05-17 06:55 PM, Alex Deucher wrote:
>>>>>> If the pin domain is set to GTT | VRAM, look at the preferred domains
>>>>>> for the bo and respect that if it's been set explicitly.
>>>>>>
>>>>>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>>>>>> ---
>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>>>>>>    1 file changed, 7 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>> index 6a9e46ae7f0a..16192f17653e 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo
>>>>>> *bo, u32 domain,
>>>>>>         * See function amdgpu_display_supported_domains()
>>>>>>         */
>>>>>>        if (domain == (AMDGPU_GEM_DOMAIN_VRAM |
>>>>>> AMDGPU_GEM_DOMAIN_GTT)) {
>>>>>> -            domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>>>> -            if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>>>> +            if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>>>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user
>>>>>> really wants vram, respect it */
>>>>>> +            else if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_GTT)
>>>>>> +                    domain = AMDGPU_GEM_DOMAIN_GTT; /* if user
>>>>>> really wants gtt, respect it */
>>>>> I'd spell VRAM and GTT in capital letters in the comments.
>>>>>
>>>>>
>>>>>> +            else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>>>>                        domain = AMDGPU_GEM_DOMAIN_GTT;
>>>>>> +            else
>>>>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>>>>        }
>>>>> Is everything in place to deal with any issues that might occur when
>>>>> flipping between buffers in VRAM and GTT?
>>>>>
>>>> Besides this question, I am also wondering how to deal with the first
>>>> display buffer created in kernel at amdgpufb_create_pinned_object()?
>>> amdgpufb_create_pinned_object() calls
>>> amdgpu_display_supported_domains() for the initial domain and
>>> amdgpu_gem_object_create() uses that for the preferred domain so it
>>> won't change the behavior there.
>> That was actually something I was not sure about when I initially
>> created the patch.
>>
>> See the FB emulation expects some pointer into a linear PCI resource
>> (VRAM), I'm not sure if that can actually deal with something kmapped
>> into the vmap (GTT).
>>
>> Since this is seldom used and only with low resolution
> It's not that low resolution these days (normally the smallest native
> resolution of all connected displays, i.e. generally >= 1920x1080), i.e.
> on the order of ~10 MB of VRAM that can't be used for anything else.

Hui, what? Isn't the fb freed after X takes over?

>> it might be better to do the conservative approach and use VRAM here.
> Or somebody could try forcing GTT for this, and see what happens. :) If
> it works, I'd say GTT is actually preferable for this.

GTT is certainly preferable. Could just be that some common fb code 
calls io*map() on this and wonders why that fails horrible :)

I think as long as we don't see a crash during startup with boot screens 
everything should be fine.

Christian.

>> And we do a full mode set when switching away from FB emulation AFAIK,
>> so the move from VRAM to GTT shouldn't be a problem.
> Agreed.
>
>

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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Michel Dänzer]

On 2018-05-22 11:11 AM, Christian König wrote:
> Am 22.05.2018 um 09:22 schrieb Michel Dänzer:
>> On 2018-05-19 05:59 PM, Christian König wrote:
>>> Am 18.05.2018 um 21:16 schrieb Alex Deucher:
>>>> On Fri, May 18, 2018 at 2:22 PM, Samuel Li <samuel.li@amd.com> wrote:
>>>>> On 2018-05-18 04:21 AM, Michel Dänzer wrote:
>>>>>> On 2018-05-17 06:55 PM, Alex Deucher wrote:
>>>>>>> If the pin domain is set to GTT | VRAM, look at the preferred
>>>>>>> domains
>>>>>>> for the bo and respect that if it's been set explicitly.
>>>>>>>
>>>>>>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>>>>>>> ---
>>>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +++++++--
>>>>>>>    1 file changed, 7 insertions(+), 2 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>>> index 6a9e46ae7f0a..16192f17653e 100644
>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>>>>>>> @@ -704,9 +704,14 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo
>>>>>>> *bo, u32 domain,
>>>>>>>         * See function amdgpu_display_supported_domains()
>>>>>>>         */
>>>>>>>        if (domain == (AMDGPU_GEM_DOMAIN_VRAM |
>>>>>>> AMDGPU_GEM_DOMAIN_GTT)) {
>>>>>>> -            domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>>>>> -            if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>>>>> +            if (bo->preferred_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>>>>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM; /* if user
>>>>>>> really wants vram, respect it */
>>>>>>> +            else if (bo->preferred_domains ==
>>>>>>> AMDGPU_GEM_DOMAIN_GTT)
>>>>>>> +                    domain = AMDGPU_GEM_DOMAIN_GTT; /* if user
>>>>>>> really wants gtt, respect it */
>>>>>> I'd spell VRAM and GTT in capital letters in the comments.
>>>>>>
>>>>>>
>>>>>>> +            else if (adev->gmc.real_vram_size <=
>>>>>>> AMDGPU_SG_THRESHOLD)
>>>>>>>                        domain = AMDGPU_GEM_DOMAIN_GTT;
>>>>>>> +            else
>>>>>>> +                    domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>>>>>        }
>>>>>> Is everything in place to deal with any issues that might occur when
>>>>>> flipping between buffers in VRAM and GTT?
>>>>>>
>>>>> Besides this question, I am also wondering how to deal with the first
>>>>> display buffer created in kernel at amdgpufb_create_pinned_object()?
>>>> amdgpufb_create_pinned_object() calls
>>>> amdgpu_display_supported_domains() for the initial domain and
>>>> amdgpu_gem_object_create() uses that for the preferred domain so it
>>>> won't change the behavior there.
>>> That was actually something I was not sure about when I initially
>>> created the patch.
>>>
>>> See the FB emulation expects some pointer into a linear PCI resource
>>> (VRAM), I'm not sure if that can actually deal with something kmapped
>>> into the vmap (GTT).
>>>
>>> Since this is seldom used and only with low resolution
>> It's not that low resolution these days (normally the smallest native
>> resolution of all connected displays, i.e. generally >= 1920x1080), i.e.
>> on the order of ~10 MB of VRAM that can't be used for anything else.
> 
> Hui, what? Isn't the fb freed after X takes over?

Nope, that isn't possible (not even un-pinning it from VRAM), because
the console layer can try accessing the buffer at any time from any context.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer
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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Christian König]

[SNIP]
>>> It's not that low resolution these days (normally the smallest native
>>> resolution of all connected displays, i.e. generally >= 1920x1080), i.e.
>>> on the order of ~10 MB of VRAM that can't be used for anything else.
>> Hui, what? Isn't the fb freed after X takes over?
> Nope, that isn't possible (not even un-pinning it from VRAM), because
> the console layer can try accessing the buffer at any time from any context.

Ok, that at least explains why people are wanting to get rid of it so 
desperately :)

Thanks,
Christian.
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Re: [PATCH] drm/amdgpu: consider user preference when pinning for SG display

[Michel Dänzer]

On 2018-05-18 09:12 PM, Alex Deucher wrote:
> On Fri, May 18, 2018 at 4:21 AM, Michel Dänzer <michel@daenzer.net> wrote:
>> On 2018-05-17 06:55 PM, Alex Deucher wrote:
>>> If the pin domain is set to GTT | VRAM, look at the preferred domains
>>> for the bo and respect that if it's been set explicitly.
>>>
>>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>
> [...]
>
>>> +             else if (adev->gmc.real_vram_size <= AMDGPU_SG_THRESHOLD)
>>>                       domain = AMDGPU_GEM_DOMAIN_GTT;
>>> +             else
>>> +                     domain = AMDGPU_GEM_DOMAIN_VRAM;
>>>       }
>>
>> Is everything in place to deal with any issues that might occur when
>> flipping between buffers in VRAM and GTT?
> 
> Ah, right, I forgot about that, we still need to do that.  In practice
> I don't think this will change anything compared things now at least
> the way mesa is currently configured.  I can hold off on this this
> patch for now until we handle that if you think it will be an issue.

Apart from relying on userspace behaviour, it could be an issue when a
DRI3 client using a different driver than glamor (e.g. Vulkan or
amdgpu-pro OpenGL) starts or stops page flipping (both cases involve a
flip between a server-allocated and a client-allocated buffer).


-- 
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Libre software enthusiast             |             Mesa and X developer
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