Re: [Intel-gfx] [PATCH 2/2] drm/i915/display: Do not use stolen on MTL

[Nirmoy Das <nirmoy.das@linux.intel.com>]

Hi Tvrkto,

On 7/6/2023 3:43 PM, Tvrtko Ursulin wrote:
>
> On 06/07/2023 14:35, Nirmoy Das wrote:
>>
>> On 7/6/2023 3:32 PM, Tvrtko Ursulin wrote:
>>>
>>> On 30/06/2023 18:01, Nirmoy Das wrote:
>>>> Use smem on MTL due to a HW bug in MTL that prevents
>>>> reading from stolen memory using LMEM BAR.
>>>
>>> Does anything remain in stolen or could the memory region just not 
>>> be created?
>>
>>
>> GSC requires DSM which can't use smem for another bug.
>
> Okay, thanks.
>
> As a related comment, these if-if-if object creation ladders were 
> always a bit ugly and some years ago I was suggesting we create a 
> helper with some "intent/usage" flags. Which could then dtrt ie. 
> create the right object for that intent/usage and platform. I *think* 
> I possibly even had a RFC... need to try and find it.


Did you find it :) Would be nice to have a better way to detect and 
apply memory region as per platfrom/usecase.


Regards,

Nirmoy

>
> Regards,
>
> Tvrtko
>
>>
>> Regards,
>>
>> Nirmoy
>>
>>
>>>
>>> Regards,
>>>
>>> Tvrtko
>>>
>>>> Cc: Oak Zeng <oak.zeng@intel.com>
>>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>>> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>>>> Cc: Andi Shyti <andi.shyti@linux.intel.com>
>>>> Cc: Andrzej Hajda <andrzej.hajda@intel.com>
>>>> Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
>>>> ---
>>>>   drivers/gpu/drm/i915/display/intel_fbdev.c   | 2 ++
>>>>   drivers/gpu/drm/i915/display/intel_overlay.c | 7 ++++---
>>>>   2 files changed, 6 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c 
>>>> b/drivers/gpu/drm/i915/display/intel_fbdev.c
>>>> index 1cc0ddc6a310..10e38d60f9ef 100644
>>>> --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
>>>> +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
>>>> @@ -182,6 +182,8 @@ static int intelfb_alloc(struct drm_fb_helper 
>>>> *helper,
>>>>           obj = i915_gem_object_create_lmem(dev_priv, size,
>>>>                             I915_BO_ALLOC_CONTIGUOUS |
>>>>                             I915_BO_ALLOC_USER);
>>>> +    } else if (IS_METEORLAKE(dev_priv)) { /* Wa_22018444074 */
>>>> +        obj = i915_gem_object_create_shmem(dev_priv, size);
>>>>       } else {
>>>>           /*
>>>>            * If the FB is too big, just don't use it since fbdev is 
>>>> not very
>>>> diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c 
>>>> b/drivers/gpu/drm/i915/display/intel_overlay.c
>>>> index d6fe2bbabe55..05ae446c8a56 100644
>>>> --- a/drivers/gpu/drm/i915/display/intel_overlay.c
>>>> +++ b/drivers/gpu/drm/i915/display/intel_overlay.c
>>>> @@ -1348,12 +1348,13 @@ int intel_overlay_attrs_ioctl(struct 
>>>> drm_device *dev, void *data,
>>>>   static int get_registers(struct intel_overlay *overlay, bool 
>>>> use_phys)
>>>>   {
>>>>       struct drm_i915_private *i915 = overlay->i915;
>>>> -    struct drm_i915_gem_object *obj;
>>>> +    struct drm_i915_gem_object *obj = NULL;
>>>>       struct i915_vma *vma;
>>>>       int err;
>>>>   -    obj = i915_gem_object_create_stolen(i915, PAGE_SIZE);
>>>> -    if (IS_ERR(obj))
>>>> +    if (!IS_METEORLAKE(i915)) /* Wa_22018444074 */
>>>> +        obj = i915_gem_object_create_stolen(i915, PAGE_SIZE);
>>>> +    if (IS_ERR_OR_NULL(obj))
>>>>           obj = i915_gem_object_create_internal(i915, PAGE_SIZE);
>>>>       if (IS_ERR(obj))
>>>>           return PTR_ERR(obj);