Re: [PATCH 07/12] drm/xe: Add device flag to indicate standalone MERT

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Tue, 21 Oct 2025 22:17:39 -0700, Lucas De Marchi wrote:
>
> From: Lukasz Laguna <lukasz.laguna@intel.com>
>
> The MERT subsystem manages memory accesses between host and device. On
> the Crescent Island platform, it requires direct management by the
> driver.
>
> Introduce a device flag and corresponding helpers to identify platforms
> with standalone MERT, enabling proper initialization and handling.

Looks like all future dGfx products may or may not have this, so we need a
has_mert flag, such as introduced here. So this LGTM:

Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>

>
> Signed-off-by: Lukasz Laguna <lukasz.laguna@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_device.h       | 5 +++++
>  drivers/gpu/drm/xe/xe_device_types.h | 2 ++
>  drivers/gpu/drm/xe/xe_pci.c          | 2 ++
>  drivers/gpu/drm/xe/xe_pci_types.h    | 1 +
>  4 files changed, 10 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
> index 32cc6323b7f64..6604b89330d51 100644
> --- a/drivers/gpu/drm/xe/xe_device.h
> +++ b/drivers/gpu/drm/xe/xe_device.h
> @@ -172,6 +172,11 @@ static inline bool xe_device_has_lmtt(struct xe_device *xe)
>	return IS_DGFX(xe);
>  }
>
> +static inline bool xe_device_has_mert(struct xe_device *xe)
> +{
> +	return xe->info.has_mert;
> +}
> +
>  u32 xe_device_ccs_bytes(struct xe_device *xe, u64 size);
>
>  void xe_device_snapshot_print(struct xe_device *xe, struct drm_printer *p);
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index f1e3b16897d1b..fb401809fae5a 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -305,6 +305,8 @@ struct xe_device {
>		 * pcode mailbox commands.
>		 */
>		u8 has_mbx_power_limits:1;
> +		/** @info.has_mert: Device has standalone MERT */
> +		u8 has_mert:1;
>		/** @info.has_pxp: Device has PXP support */
>		u8 has_pxp:1;
>		/** @info.has_range_tlb_inval: Has range based TLB invalidations */
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index 000bb30b97712..ef27d17d904b8 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -403,6 +403,7 @@ static const struct xe_device_desc cri_desc = {
>	.has_display = false,
>	.has_flat_ccs = false,
>	.has_mbx_power_limits = true,
> +	.has_mert = true,
>	.has_sriov = true,
>	.max_gt_per_tile = 2,
>	.require_force_probe = true,
> @@ -669,6 +670,7 @@ static int xe_info_init_early(struct xe_device *xe,
>	xe->info.has_heci_cscfi = desc->has_heci_cscfi;
>	xe->info.has_late_bind = desc->has_late_bind;
>	xe->info.has_llc = desc->has_llc;
> +	xe->info.has_mert = desc->has_mert;
>	xe->info.has_pxp = desc->has_pxp;
>	xe->info.has_sriov = xe_configfs_primary_gt_allowed(to_pci_dev(xe->drm.dev)) &&
>		desc->has_sriov;
> diff --git a/drivers/gpu/drm/xe/xe_pci_types.h b/drivers/gpu/drm/xe/xe_pci_types.h
> index a4451bdc79fb3..3e3bcdd1d1cf1 100644
> --- a/drivers/gpu/drm/xe/xe_pci_types.h
> +++ b/drivers/gpu/drm/xe/xe_pci_types.h
> @@ -46,6 +46,7 @@ struct xe_device_desc {
>	u8 has_late_bind:1;
>	u8 has_llc:1;
>	u8 has_mbx_power_limits:1;
> +	u8 has_mert:1;
>	u8 has_pxp:1;
>	u8 has_sriov:1;
>	u8 needs_scratch:1;
>
> --
> 2.51.0
>