On Thu, Jul 27, 2023 at 03:54:58PM +0100, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
>
> No need to run extra instructions which will never trigger on platforms
> before Meteorlake.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> index c8568e5d1147..862ac1d2de25 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> @@ -63,6 +63,30 @@ static u64 gen12_pte_encode(dma_addr_t addr,
> {
> gen8_pte_t pte = addr | GEN8_PAGE_PRESENT | GEN8_PAGE_RW;
>
> + if (unlikely(flags & PTE_READ_ONLY))
> + pte &= ~GEN8_PAGE_RW;
> +
> + if (flags & PTE_LM)
> + pte |= GEN12_PPGTT_PTE_LM;
> +
> + if (pat_index & BIT(0))
> + pte |= GEN12_PPGTT_PTE_PAT0;
> +
> + if (pat_index & BIT(1))
> + pte |= GEN12_PPGTT_PTE_PAT1;
> +
> + if (pat_index & BIT(2))
> + pte |= GEN12_PPGTT_PTE_PAT2;
> +
> + return pte;
> +}
> +
> +static u64 mtl_pte_encode(dma_addr_t addr,
> + unsigned int pat_index,
> + u32 flags)
> +{
> + gen8_pte_t pte = addr | GEN8_PAGE_PRESENT | GEN8_PAGE_RW;
> +
Would it be more readable to start with
gen8_pte_t pte = gen12_pte_encode(addr, pat_index, flags);
and then |-in only the MTL-specific bit(s) as appropriate?
> if (unlikely(flags & PTE_READ_ONLY))
> pte &= ~GEN8_PAGE_RW;
>
> @@ -995,6 +1019,8 @@ struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt,
> */
> ppgtt->vm.alloc_scratch_dma = alloc_pt_dma;
>
> + if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 70))
> + ppgtt->vm.pte_encode = mtl_pte_encode;
> if (GRAPHICS_VER(gt->i915) >= 12)
> ppgtt->vm.pte_encode = gen12_pte_encode;
I think you wanted 'else if' here. Otherwise you clobber the MTL
function pointer.
Matt
> else
> --
> 2.39.2
>
--
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation
