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

[Tvrtko Ursulin]

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.

Regards,

Tvrtko

> 
> Regards,
> 
> Nirmoy
> 
> 
>>
>> Regards,
>>
>> Tvrtko
>>
>>> Cc: Oak Zeng <oak.zeng at intel.com>
>>> Cc: Jani Nikula <jani.nikula at linux.intel.com>
>>> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
>>> Cc: Andi Shyti <andi.shyti at linux.intel.com>
>>> Cc: Andrzej Hajda <andrzej.hajda at intel.com>
>>> Signed-off-by: Nirmoy Das <nirmoy.das at 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);