Re: [PATCH] drm/xe/display: mark DPT with XE_BO_PAGETABLE

[Matthew Auld <matthew.auld@intel.com>]

On 14/03/2024 17:00, Lucas De Marchi wrote:
> On Thu, Mar 14, 2024 at 04:49:06PM +0000, Matthew Auld wrote:
>> Otherwise in the case where we use normal system memory, the CPU access
>> will always be cached, like when filling the DPT PTEs, which is likely
>> not what we want since HW access could be incoherent on platforms like
>> LNL. Marking as XE_BO_PAGETABLE will force wc/uc underneath on such
>> platforms.
>>
>> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
>> Cc: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
> 
> 
> Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>

Thanks.

> 
> humn... since you're touching these flags, could you take a look at
> https://lore.kernel.org/intel-xe/20240314052619.2628396-1-lucas.demarchi@intel.com/ ?

Sure, will take a look now.

> 
> thanks
> Lucas De Marchi
> 
>> ---
>> drivers/gpu/drm/xe/display/xe_fb_pin.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/display/xe_fb_pin.c 
>> b/drivers/gpu/drm/xe/display/xe_fb_pin.c
>> index 722c84a56607..b220f136be70 100644
>> --- a/drivers/gpu/drm/xe/display/xe_fb_pin.c
>> +++ b/drivers/gpu/drm/xe/display/xe_fb_pin.c
>> @@ -100,17 +100,20 @@ static int __xe_pin_fb_vma_dpt(struct 
>> intel_framebuffer *fb,
>>         dpt = xe_bo_create_pin_map(xe, tile0, NULL, dpt_size,
>>                        ttm_bo_type_kernel,
>>                        XE_BO_CREATE_VRAM0_BIT |
>> -                       XE_BO_CREATE_GGTT_BIT);
>> +                       XE_BO_CREATE_GGTT_BIT |
>> +                       XE_BO_PAGETABLE);
>>     else
>>         dpt = xe_bo_create_pin_map(xe, tile0, NULL, dpt_size,
>>                        ttm_bo_type_kernel,
>>                        XE_BO_CREATE_STOLEN_BIT |
>> -                       XE_BO_CREATE_GGTT_BIT);
>> +                       XE_BO_CREATE_GGTT_BIT |
>> +                       XE_BO_PAGETABLE);
>>     if (IS_ERR(dpt))
>>         dpt = xe_bo_create_pin_map(xe, tile0, NULL, dpt_size,
>>                        ttm_bo_type_kernel,
>>                        XE_BO_CREATE_SYSTEM_BIT |
>> -                       XE_BO_CREATE_GGTT_BIT);
>> +                       XE_BO_CREATE_GGTT_BIT |
>> +                       XE_BO_PAGETABLE);
>>     if (IS_ERR(dpt))
>>         return PTR_ERR(dpt);
>>
>> -- 
>> 2.44.0
>>