Re: [PATCH] drm/xe/query: Only advertise NO_COMPRESSION hint on devices with flat CCS

["Souza, Jose" <jose.souza@intel.com>]

On Thu, 2026-02-05 at 14:17 +0000, Matthew Auld wrote:
> On 05/02/2026 13:43, Souza, Jose wrote:
> > On Thu, 2026-02-05 at 13:50 +0530, Sanjay Yadav wrote:
> > > Devices like CRI have GRAPHICS_VER >= 20 but don't have
> > > compression
> > > support their PAT table (xe3p_xpc_pat_table) has no compression-
> > > enabled
> > > entries.
> > > 
> > > Only advertise HAS_NO_COMPRESSION_HINT flag when the device
> > > actually
> > > has
> > > flat CCS and thus compression capability.
> > 
> > Is this change required to fix a bug? Semantically, it doesn't make
> > much sense. If a device doesn't support compression and we pass
> > DRM_XE_GEM_CREATE_FLAG_NO_COMPRESSION during BO creation, I don't
> > see a
> > problem with it. You could optimize and always enable this flag
> > internally for this device, but passing it during creation isn't
> > wrong.
> 
> Yeah, there is no real bug. But having HAS_NO_COMPRESSION return
> false 
> to reflect that tagging buffers with NO_COMPRESSION is not 
> relevant/needed on this device, since compression as a feature is
> either 
> disabled or does not even exist in the hw, also seems reasonable.
> 
> The motivation was originally IGT, just to make it a bit simpler to 
> detect when this flag is bogus, on certain platforms. And from UMD
> pov 
> having it more accurately reflect whether using this flag is relevant
> or 
> not seemed reasonable.
> 
> We can try to so fix the IGT issue in another way, without touching
> this 
> flag, if preferred.

If the reason is IGT I would fix it there. Do less changes in KMD as
possible but up to you.
Mesa is ready for both cases.

> 
> > 
> > > 
> > > Fixes: 78d91ba6bd796 ("drm/xe/uapi: Add NO_COMPRESSION BO flag
> > > and
> > > query capability")
> > > Cc: Matthew Auld <matthew.auld@intel.com>
> > > Cc: José Roberto de Souza <jose.souza@intel.com>
> > > Cc: Stuart Summers <stuart.summers@intel.com>
> > > Signed-off-by: Sanjay Yadav <sanjay.kumar.yadav@intel.com>
> > > ---
> > >   drivers/gpu/drm/xe/xe_query.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/xe/xe_query.c
> > > b/drivers/gpu/drm/xe/xe_query.c
> > > index 34db266b723f..c152ebfbd7d8 100644
> > > --- a/drivers/gpu/drm/xe/xe_query.c
> > > +++ b/drivers/gpu/drm/xe/xe_query.c
> > > @@ -335,7 +335,7 @@ static int query_config(struct xe_device *xe,
> > > struct drm_xe_device_query *query)
> > >   	if (xe->info.has_usm &&
> > > IS_ENABLED(CONFIG_DRM_XE_GPUSVM))
> > >   		config->info[DRM_XE_QUERY_CONFIG_FLAGS] |=
> > >   			DRM_XE_QUERY_CONFIG_FLAG_HAS_CPU_ADDR_MI
> > > RROR
> > > ;
> > > -	if (GRAPHICS_VER(xe) >= 20)
> > > +	if (GRAPHICS_VER(xe) >= 20 &&
> > > xe_device_has_flat_ccs(xe))
> > >   		config->info[DRM_XE_QUERY_CONFIG_FLAGS] |=
> > >   			DRM_XE_QUERY_CONFIG_FLAG_HAS_NO_COMPRESS
> > > ION_
> > > HINT;
> > >   	config->info[DRM_XE_QUERY_CONFIG_FLAGS] |=