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Date:   Wed, 26 Jan 2022 14:49:26 +0100
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Subject: Re: [Intel-gfx] [PATCH v5 1/5] drm/i915: add needs_compact_pt flag
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To:     Robert Beckett <bob.beckett@collabora.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org,
        Matthew Auld <matthew.auld@intel.com>
References: <20220125193530.3272386-1-bob.beckett@collabora.com>
 <20220125193530.3272386-2-bob.beckett@collabora.com>
From:   =?UTF-8?Q?Thomas_Hellstr=c3=b6m_=28Intel=29?= 
        <thomas_os@shipmail.org>
In-Reply-To: <20220125193530.3272386-2-bob.beckett@collabora.com>
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On 1/25/22 20:35, Robert Beckett wrote:
> From: Ramalingam C <ramalingam.c@intel.com>
>
> Add a new platform flag, needs_compact_pt, to mark the requirement of
> compact pt layout support for the ppGTT when using 64K GTT pages.
>
> With this flag has_64k_pages will only indicate requirement of 64K
> GTT page sizes or larger for device local memory access.
>
> Suggested-by: Matthew Auld <matthew.auld@intel.com>
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
> ---
>   drivers/gpu/drm/i915/i915_drv.h          | 10 +++++++---
>   drivers/gpu/drm/i915/i915_pci.c          |  2 ++
>   drivers/gpu/drm/i915/intel_device_info.h |  1 +
>   3 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 44c1f98144b4..1258b7779705 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1512,12 +1512,16 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
>   
>   /*
>    * Set this flag, when platform requires 64K GTT page sizes or larger for
> - * device local memory access. Also this flag implies that we require or
> - * at least support the compact PT layout for the ppGTT when using the 64K
> - * GTT pages.

Why do we remove these comment lines?


> + * device local memory access.
>    */
>   #define HAS_64K_PAGES(dev_priv) (INTEL_INFO(dev_priv)->has_64k_pages)
>   
> +/* Set this flag when platform doesn't allow both 64k pages and 4k pages in

First line of multi-line comments should be empty.


> + * the same PT. this flag means we need to support compact PT layout for the
> + * ppGTT when using the 64K GTT pages.
> + */
> +#define NEEDS_COMPACT_PT(dev_priv) (INTEL_INFO(dev_priv)->needs_compact_pt)
> +
>   #define HAS_IPC(dev_priv)		 (INTEL_INFO(dev_priv)->display.has_ipc)
>   
>   #define HAS_REGION(i915, i) (INTEL_INFO(i915)->memory_regions & (i))
> diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> index 4081fd50ba9d..799b56569ef5 100644
> --- a/drivers/gpu/drm/i915/i915_pci.c
> +++ b/drivers/gpu/drm/i915/i915_pci.c
> @@ -1028,6 +1028,7 @@ static const struct intel_device_info xehpsdv_info = {
>   	PLATFORM(INTEL_XEHPSDV),
>   	.display = { },
>   	.has_64k_pages = 1,
> +	.needs_compact_pt = 1,
>   	.platform_engine_mask =
>   		BIT(RCS0) | BIT(BCS0) |
>   		BIT(VECS0) | BIT(VECS1) | BIT(VECS2) | BIT(VECS3) |
> @@ -1045,6 +1046,7 @@ static const struct intel_device_info dg2_info = {
>   	.media.rel = 55,
>   	PLATFORM(INTEL_DG2),
>   	.has_64k_pages = 1,
> +	.needs_compact_pt = 1,
>   	.platform_engine_mask =
>   		BIT(RCS0) | BIT(BCS0) |
>   		BIT(VECS0) | BIT(VECS1) |
> diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
> index 3699b1c539ea..c8aaf646430c 100644
> --- a/drivers/gpu/drm/i915/intel_device_info.h
> +++ b/drivers/gpu/drm/i915/intel_device_info.h
> @@ -130,6 +130,7 @@ enum intel_ppgtt_type {
>   	/* Keep has_* in alphabetical order */ \
>   	func(has_64bit_reloc); \
>   	func(has_64k_pages); \
> +	func(needs_compact_pt); \
>   	func(gpu_reset_clobbers_display); \
>   	func(has_reset_engine); \
>   	func(has_global_mocs); \