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

[Umesh Nerlige Ramappa]

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], 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?

Fixup posted here - 
https://patchwork.freedesktop.org/patch/561095/?series=124690&rev=1

Thanks,
Umesh

>
>[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
>> > > > > >
>> >