[Intel-xe] [PATCH v3 26/30] drm/xe/uapi: Add pad to drm_xe_engine_class_instance

[Francois Dugast]

On Mon, Oct 09, 2023 at 10:05:33AM -0700, Umesh Nerlige Ramappa wrote:
> On Wed, Oct 04, 2023 at 07:35:06PM -0700, Umesh Nerlige Ramappa wrote:
> > On Wed, Oct 04, 2023 at 12:55:19PM +0200, Francois Dugast wrote:
> > > On Tue, Oct 03, 2023 at 11:15:00AM -0700, Umesh Nerlige Ramappa wrote:
> > > > On Fri, Sep 29, 2023 at 09:45:35AM -0700, Souza, Jose wrote:
> > > > > On Fri, 2023-09-29 at 09:00 -0700, Umesh Nerlige Ramappa wrote:
> > > > > > On Fri, Sep 29, 2023 at 11:06:53AM +0200, Francois Dugast wrote:
> > > > > > > Hi Umesh,
> > > > > > >
> > > > > > > On Thu, Sep 28, 2023 at 05:36:39PM -0700, Umesh Nerlige Ramappa wrote:
> > > > > > > > On Tue, Sep 26, 2023 at 12:55:36PM +0000, Francois Dugast wrote:
> > > > > > > > > Add pad to reserve space for future uses such as special configurations
> > > > > > > > > for media.
> > > > > > > > >
> > > > > > > > > Signed-off-by: Francois Dugast <francois.dugast at intel.com>
> > > > > > > >
> > > > > > > > I saw a comment in v4 that you dropped the patches that are not reviewed, so
> > > > > > > > this is:
> > > > > > > >
> > > > > > > > Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
> > > > > > > >
> > > > > > > > Hoping this will be part of the final series that you merge since the
> > > > > > > > ENGINE_CYCLES query is using this structure and relies on this padding.
> > > > > > >
> > > > > > > Actually using your original submission [1] this patch should not longer
> > > > > > > be necessary, right? It includes:
> > > > > > >
> > > > > > >   __u16 rsvd;
> > > > > > >
> > > > > > > [1] https://lore.kernel.org/intel-xe/20230814223734.375449-5-umesh.nerlige.ramappa@intel.com/
> > > > > >
> > > > > > Hmmm, I failed to notice that earlier. My bad. v4 looks good, you can
> > > > > > ignore this.
> > > > > 
> > > > > It is named as rsvd but it should be a pad.
> > > > > 
> > > > > We can't leave as reserved to be future used to return media engine capabilities because drm_xe_engine_class_instance is also used as input to other
> > > > > uAPIs and that is useless information after initialization that UMDs should not need to carry around.
> > > > > 
> > > > > Instead DRM_XE_DEVICE_QUERY_ENGINES should return something like
> > > > > 
> > > > > struct drm_xe_engine_info {
> > > > > 	struct drm_xe_engine_class_instance instance;
> > > > > 	__u32 rsvd;/* future could be __u16 capabilities; __u16 rsvd; */
> > > > > };
> > > > > 
> > > > > This can be fixed in uAPI take 2.
> > > > 
> > > > Hi Francois,
> > > > 
> > > > As per Jose's inputs, I posted a new version of my series here -
> > > > https://patchwork.freedesktop.org/patch/560614/?series=124565&rev=1.
> > > > 
> > > > Can you please pick up patch 3/3 from here. Note that just adding the pad
> > > > does not resolve the issue I was mentioning in my original series.  We also
> > > > need to explicitly initialize the pad to 0 in this case. I have included
> > > > that change as well in the above patch.
> > > > 
> > > > Thanks,
> > > > Umesh
> > > 
> > > Hi Umesh,
> > > 
> > > Thanks for the update. An earlier version was already included in take 1
> > > of the uAPI changes [1],
> > 
> > Not sure if the below link in [1] is what you wanted to share. It points
> > to the series I posted. I am guessing you were intending to point to a
> > take 1 series.
> 
> fixup here - https://patchwork.freedesktop.org/series/124690/
> 
> Thanks,
> Umesh

Thanks, I will be included in uAPI take 2.

Francois

> > 
> > Thanks,
> > Umesh
> > 
> > > against which UMDs are currently aligning, so it
> > > would be best to leave take 1 as it is and include your fix as a fixup in
> > > take 2. Could you please send a fixup instead?
> > > 
> > > [1] https://patchwork.freedesktop.org/patch/560614/?series=124565&rev=1
> > > 
> > > Francois
> > > 
> > > > > 
> > > > > >
> > > > > > Thanks,
> > > > > > Umesh
> > > > > > >
> > > > > > > Francois
> > > > > > >
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Umesh
> > > > > > > > > ---
> > > > > > > > > include/uapi/drm/xe_drm.h | 2 ++
> > > > > > > > > 1 file changed, 2 insertions(+)
> > > > > > > > >
> > > > > > > > > diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
> > > > > > > > > index 79e47708d526..84091860c7d2 100644
> > > > > > > > > --- a/include/uapi/drm/xe_drm.h
> > > > > > > > > +++ b/include/uapi/drm/xe_drm.h
> > > > > > > > > @@ -143,6 +143,8 @@ struct drm_xe_engine_class_instance {
> > > > > > > > >
> > > > > > > > > 	__u16 engine_instance;
> > > > > > > > > 	__u16 gt_id;
> > > > > > > > > +	/** @pad: MBZ */
> > > > > > > > > +	__u32 pad;
> > > > > > > > > };
> > > > > > > > >
> > > > > > > > > /**
> > > > > > > > > --
> > > > > > > > > 2.34.1
> > > > > > > > >
> > > > >