[PATCH v3] drm/i915: Flush WC GGTT only on required platforms

[Andi Shyti]

Hi Nirmoy,

On Wed, Oct 18, 2023 at 11:38:15AM +0200, Nirmoy Das wrote:
> gen8_ggtt_invalidate() is only needed for limited set of platforms
> where GGTT is mapped as WC. This was added as way to fix WC based GGTT in
> commit 0f9b91c754b7 ("drm/i915: flush system agent TLBs on SNB") and
> there are no reference in HW docs that forces us to use this on non-WC
> backed GGTT.
> 
> This can also cause unwanted side-effects on XE_HP platforms where
> GFX_FLSH_CNTL_GEN6 is not valid anymore.
> 
> v2: Add a func to detect wc ggtt detection (Ville)
> v3: Improve commit log and add reference commit (Daniel)
> 
> Fixes: d2eae8e98d59 ("drm/i915/dg2: Drop force_probe requirement")

I'm wondering if this is the right Fixes, though. Should this
rather be:

Fixes: 6266992cf105 ("drm/i915/gt: remove GRAPHICS_VER == 10")

?

Andi