Re: [PATCH 1/3] drm/xe: Introduced needs_scratch bit in device descriptor

[Matthew Brost <matthew.brost@intel.com>]

On Mon, Feb 24, 2025 at 08:40:06AM -0700, Zeng, Oak wrote:
> Ping
> 
> Thomas, Matt, do you have further comments on this series?
> 

Will do a full review a bit later today.

Matt

> Oak
> 
> > -----Original Message-----
> > From: Intel-xe <intel-xe-bounces@lists.freedesktop.org> On Behalf
> > Of Oak Zeng
> > Sent: February 12, 2025 9:23 PM
> > To: intel-xe@lists.freedesktop.org
> > Cc: Thomas.Hellstrom@linux.intel.com; Brost, Matthew
> > <matthew.brost@intel.com>; Cavitt, Jonathan
> > <jonathan.cavitt@intel.com>
> > Subject: [PATCH 1/3] drm/xe: Introduced needs_scratch bit in device
> > descriptor
> > 
> > On some platform, scratch page is needed for out of bound prefetch
> > to work. Introduce a bit in device descriptor to specify whether
> > this device needs scratch page to work.
> > 
> > v2: introduce a needs_scratch bit in device info (Thomas, Jonathan)
> > 
> > Signed-off-by: Oak Zeng <oak.zeng@intel.com>
> > Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_device_types.h | 3 +++
> >  drivers/gpu/drm/xe/xe_pci.c          | 5 +++++
> >  2 files changed, 8 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_device_types.h
> > b/drivers/gpu/drm/xe/xe_device_types.h
> > index 833c29fed3a3..a5ba9e4e470f 100644
> > --- a/drivers/gpu/drm/xe/xe_device_types.h
> > +++ b/drivers/gpu/drm/xe/xe_device_types.h
> > @@ -46,6 +46,7 @@ struct xe_pxp;
> >  #define GRAPHICS_VERx100(xe) ((xe)->info.graphics_verx100)
> >  #define MEDIA_VERx100(xe) ((xe)->info.media_verx100)
> >  #define IS_DGFX(xe) ((xe)->info.is_dgfx)
> > +#define NEEDS_SCRATCH(xe) ((xe)->info.needs_scratch)
> > 
> >  #define XE_VRAM_FLAGS_NEED64K		BIT(0)
> > 
> > @@ -318,6 +319,8 @@ struct xe_device {
> >  		u8 has_usm:1;
> >  		/** @info.is_dgfx: is discrete device */
> >  		u8 is_dgfx:1;
> > +		/** @info.needs_scratch: needs scratch page for oob
> > prefetch to work */
> > +		u8 needs_scratch:1;
> >  		/**
> >  		 * @info.probe_display: Probe display hardware.  If
> > set to
> >  		 * false, the driver will behave as if there is no display
> > diff --git a/drivers/gpu/drm/xe/xe_pci.c
> > b/drivers/gpu/drm/xe/xe_pci.c
> > index 6a8e82aff385..c614f673efa5 100644
> > --- a/drivers/gpu/drm/xe/xe_pci.c
> > +++ b/drivers/gpu/drm/xe/xe_pci.c
> > @@ -67,6 +67,7 @@ struct xe_device_desc {
> >  	u8 has_llc:1;
> >  	u8 has_pxp:1;
> >  	u8 has_sriov:1;
> > +	u8 needs_scratch:1;
> >  	u8 skip_guc_pc:1;
> >  	u8 skip_mtcfg:1;
> >  	u8 skip_pcode:1;
> > @@ -353,6 +354,7 @@ static const struct xe_device_desc lnl_desc = {
> >  	.dma_mask_size = 46,
> >  	.has_display = true,
> >  	.has_pxp = true,
> > +	.needs_scratch = true,
> >  };
> > 
> >  static const struct xe_device_desc bmg_desc = {
> > @@ -361,6 +363,7 @@ static const struct xe_device_desc bmg_desc =
> > {
> >  	.dma_mask_size = 46,
> >  	.has_display = true,
> >  	.has_heci_cscfi = 1,
> > +	.needs_scratch = true,
> >  };
> > 
> >  static const struct xe_device_desc ptl_desc = {
> > @@ -369,6 +372,7 @@ static const struct xe_device_desc ptl_desc = {
> >  	.has_display = true,
> >  	.has_sriov = true,
> >  	.require_force_probe = true,
> > +	.needs_scratch = true,
> >  };
> > 
> >  #undef PLATFORM
> > @@ -644,6 +648,7 @@ static int xe_info_init_early(struct xe_device
> > *xe,
> >  	xe->info.skip_guc_pc = desc->skip_guc_pc;
> >  	xe->info.skip_mtcfg = desc->skip_mtcfg;
> >  	xe->info.skip_pcode = desc->skip_pcode;
> > +	xe->info.needs_scratch = desc->needs_scratch;
> > 
> >  	xe->info.probe_display =
> > IS_ENABLED(CONFIG_DRM_XE_DISPLAY) &&
> >  				 xe_modparam.probe_display &&
> > --
> > 2.26.3
>