Re: [PATCH 1/2] drm/xe/oa: Rename last argument of WHITELIST_OA_MMIO_TRG

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

On Wed, 03 Jun 2026 12:09:59 -0700, Umesh Nerlige Ramappa wrote:
>
> On Tue, Jun 02, 2026 at 04:09:07PM -0700, Ashutosh Dixit wrote:
> > OA head pointer registers are not used by UMD's and do not need to be
> > whitelisted, the last argument of WHITELIST_OA_MMIO_TRG is actually used
> > for whitelisting tail pointer and OA buffer registers. Rename the argument
> > to tail_buf to highlight this. OA head pointer is sometimes provided to the
> > WHITELIST_OA_MMIO_TRG to have the correct register offset alignment (16)
> > for RING_FORCE_TO_NONPRIV_RANGE_4.
> >
> > Fixes: ed455775c5a6 ("drm/xe/rtp: Refactor OAG MMIO trigger register whitelisting")
> > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> > ---
> > drivers/gpu/drm/xe/xe_reg_whitelist.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_reg_whitelist.c b/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > index 2e84b1c49f374..a17ebacc1455b 100644
> > --- a/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > +++ b/drivers/gpu/drm/xe/xe_reg_whitelist.c
> > @@ -104,10 +104,10 @@ static const struct xe_rtp_table_sr register_whitelist = XE_RTP_TABLE_SR(
> >				   RING_FORCE_TO_NONPRIV_ACCESS_RW))
> >	},
> >
> > -#define WHITELIST_OA_MMIO_TRG(trg, status, head) \
> > +#define WHITELIST_OA_MMIO_TRG(trg, status, tail_buf) \
> >	WHITELIST(trg, RING_FORCE_TO_NONPRIV_ACCESS_RW), \
> >	WHITELIST(status, RING_FORCE_TO_NONPRIV_ACCESS_RD), \
> > -	WHITELIST(head, RING_FORCE_TO_NONPRIV_ACCESS_RD | RING_FORCE_TO_NONPRIV_RANGE_4)
> > +	WHITELIST(tail_buf, RING_FORCE_TO_NONPRIV_ACCESS_RD | RING_FORCE_TO_NONPRIV_RANGE_4)
>
> I think this would be a good time to split the regs and do away with the
> RANGE_4.  If HEAD and STATUS are not used, then we should just use 2 slots
> - one for OA_TAIL and one for OA_BUFFER (single reg mode). Any idea if
> STATUS is needed? I thought the KMD already returns the status in an IOCTL.

OK, yes I think OASTATUS doesn't need to be whitelisted and we can also do
away with RANGE_4.

But can we review and merge Patch 2 for now, since that is a bug fix and
will need to be propagated also to previous kernel versions. So if we can
merge that first and then make these changes, it will simplify life quite a
bit.

Thanks.
--
Ashutosh


>
> >
> > #define WHITELIST_OAG_MMIO_TRG \
> >	WHITELIST_OA_MMIO_TRG(OAG_MMIOTRIGGER, OAG_OASTATUS, OAG_OAHEADPTR)
> > --
> > 2.54.0
> >