Re: [Mesa-dev] [Intel-gfx] [PATCH] drm/i915/gt: Add separate MOCS table for Gen12 devices other than TGL/RKL
On Thu, Sep 09, 2021 at 10:59:36PM +0300, Ville Syrjälä wrote:
> On Thu, Sep 09, 2021 at 11:14:15AM -0700, Matt Roper wrote:
> > On Thu, Sep 09, 2021 at 08:42:15PM +0300, Ville Syrjälä wrote:
> > > On Thu, Sep 09, 2021 at 10:15:56AM -0700, Matt Roper wrote:
> > > > On Thu, Sep 09, 2021 at 06:09:55PM +0300, Ville Syrjälä wrote:
> > > > > On Thu, Sep 09, 2021 at 08:00:02AM -0700, Matt Roper wrote:
> > > > > > On Thu, Sep 09, 2021 at 05:39:26PM +0300, Ville Syrjälä wrote:
> > > > > > > On Thu, Sep 09, 2021 at 07:29:33AM -0700, Matt Roper wrote:
> > > > > > > > On Thu, Sep 09, 2021 at 04:58:50PM +0300, Ville Syrjälä wrote:
> > > > > > > > > On Tue, Sep 07, 2021 at 11:19:29AM -0700, Matt Roper wrote:
> > > > > > > > > > On Tue, Sep 07, 2021 at 08:41:06PM +0300, Ville Syrjälä
> > > > > > > > > > wrote:
> > > > > > > > > > > On Tue, Sep 07, 2021 at 10:27:28AM -0700, Matt Roper
> > > > > > > > > > > wrote:
> > > > > > > > > > > > On Tue, Sep 07, 2021 at 10:46:39PM +0530, Ayaz A
> > > > > > > > > > > > Siddiqui wrote:
> > > > > > > > > > > > > MOCS table of TGL/RKL has MOCS[1] set to L3_UC.
> > > > > > > > > > > > > While for other gen12 devices we need to set MOCS[1]
> > > > > > > > > > > > > as L3_WB,
> > > > > > > > > > > > > So adding a new MOCS table for other gen 12 devices
> > > > > > > > > > > > > eg. ADL.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Fixes: cfbe5291a189 ("drm/i915/gt: Initialize unused
> > > > > > > > > > > > > MOCS entries with device specific values")
> > > > > > > > > > > > > Cc: Matt Roper
> > > > > > > > > > > > > Signed-off-by: Ayaz A Siddiqui
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Yep, we overlooked that the TGL table still had an
> > > > > > > > > > > > explicit entry for
> > > > > > > > > > > > I915_MOCS_PTE and wasn't just using an implicit
> > > > > > > > > > > > 'unused_entries' lookup
> > > > > > > > > > > > for MOCS[1]. The new table is the same as the TGL
> > > > > > > > > > > > table, just with
> > > > > > > > > > > > I915_MOCS_PTE (1) removed.
> > > > > > > > > > >
> > > > > > > > > > > And just how are people planning on handling display
> > > > > > > > > > > cacheability
> > > > > > > > > > > control without a PTE MOCS entry? Is Mesa/etc. already
> > > > > > > > > > > making all
> > > > > > > > > > > external bos uncached on these platforms just in case we
> > > > > > > > > > > might
> > > > > > > > > > > scan out said bo?
> > > > > > > > > >
> > > > > > > > > > MOCS entry 1 has never been considered a valid MOCS table
> > > > > > > > > > entry on gen12
> > > > > > > > > > platforms (despite the old #define, it's not actually
> > > > > > > > > > related to PTE,
> > > > > > > > > > display, etc. anymore).
> > > > > > > > >
> > > > > > > > > So can someone finally explain to me how we're supposed to
> > > > > > > > > cache
> > > > > > > > > anything that might become a scanout buffer later (eg. window
> > > > > > > > > system
> > > > > > > > > buffers)? Or are we just making everything like that UC now,
> > > > > > > > > and is
> > > > > > > > > everyone happy with that? Is userspace actually following
> > > > > > > > > that?
> > > > > > > >
> > > > >
Re: [Mesa-dev] [Intel-gfx] [PATCH] drm/i915/gt: Add separate MOCS table for Gen12 devices other than TGL/RKL
On Thu, Sep 09, 2021 at 08:42:15PM +0300, Ville Syrjälä wrote:
> On Thu, Sep 09, 2021 at 10:15:56AM -0700, Matt Roper wrote:
> > On Thu, Sep 09, 2021 at 06:09:55PM +0300, Ville Syrjälä wrote:
> > > On Thu, Sep 09, 2021 at 08:00:02AM -0700, Matt Roper wrote:
> > > > On Thu, Sep 09, 2021 at 05:39:26PM +0300, Ville Syrjälä wrote:
> > > > > On Thu, Sep 09, 2021 at 07:29:33AM -0700, Matt Roper wrote:
> > > > > > On Thu, Sep 09, 2021 at 04:58:50PM +0300, Ville Syrjälä wrote:
> > > > > > > On Tue, Sep 07, 2021 at 11:19:29AM -0700, Matt Roper wrote:
> > > > > > > > On Tue, Sep 07, 2021 at 08:41:06PM +0300, Ville Syrjälä wrote:
> > > > > > > > > On Tue, Sep 07, 2021 at 10:27:28AM -0700, Matt Roper wrote:
> > > > > > > > > > On Tue, Sep 07, 2021 at 10:46:39PM +0530, Ayaz A Siddiqui
> > > > > > > > > > wrote:
> > > > > > > > > > > MOCS table of TGL/RKL has MOCS[1] set to L3_UC.
> > > > > > > > > > > While for other gen12 devices we need to set MOCS[1] as
> > > > > > > > > > > L3_WB,
> > > > > > > > > > > So adding a new MOCS table for other gen 12 devices eg.
> > > > > > > > > > > ADL.
> > > > > > > > > > >
> > > > > > > > > > > Fixes: cfbe5291a189 ("drm/i915/gt: Initialize unused MOCS
> > > > > > > > > > > entries with device specific values")
> > > > > > > > > > > Cc: Matt Roper
> > > > > > > > > > > Signed-off-by: Ayaz A Siddiqui
> > > > > > > > > >
> > > > > > > > > > Yep, we overlooked that the TGL table still had an explicit
> > > > > > > > > > entry for
> > > > > > > > > > I915_MOCS_PTE and wasn't just using an implicit
> > > > > > > > > > 'unused_entries' lookup
> > > > > > > > > > for MOCS[1]. The new table is the same as the TGL table,
> > > > > > > > > > just with
> > > > > > > > > > I915_MOCS_PTE (1) removed.
> > > > > > > > >
> > > > > > > > > And just how are people planning on handling display
> > > > > > > > > cacheability
> > > > > > > > > control without a PTE MOCS entry? Is Mesa/etc. already making
> > > > > > > > > all
> > > > > > > > > external bos uncached on these platforms just in case we might
> > > > > > > > > scan out said bo?
> > > > > > > >
> > > > > > > > MOCS entry 1 has never been considered a valid MOCS table entry
> > > > > > > > on gen12
> > > > > > > > platforms (despite the old #define, it's not actually related
> > > > > > > > to PTE,
> > > > > > > > display, etc. anymore).
> > > > > > >
> > > > > > > So can someone finally explain to me how we're supposed to cache
> > > > > > > anything that might become a scanout buffer later (eg. window
> > > > > > > system
> > > > > > > buffers)? Or are we just making everything like that UC now, and
> > > > > > > is
> > > > > > > everyone happy with that? Is userspace actually following that?
> > > > > >
> > > > > > Table entry #1 has never had anything to do with scanout on gen12+.
> > > > > > I
> > > > > > would assume that UMDs are either using the display entry in the
> > > > > > MOCS
> > > > > > table (which is 61 on gen12+) or some other UC entry.
> > > > >
> > > > > If 61 is meant to to be the new PTE entry wy hasn't it been defines as
> > > > > such in the code? And I know for a fact that userspace (Mesa) is not
> > > >
> > > > There is no "PTE" entry anymore. But 61 is already documented as
> > > > "displayable" in both the spec and the code:
> > > >
> > > > /* HW Special Case (Displayable) */
> > > >
> > > > MOCS_ENTRY(61,
>
