Re: [Mesa3d-dev] Mesa (gallium-resources): gallium: fix comments for changed USAGE flags

[José F. <jfo...@vm...>]

On Fri, 2010-04-09 at 09:22 -0700, José Fonseca wrote:
> On Fri, 2010-04-09 at 09:02 -0700, Keith Whitwell wrote:
> > On Fri, 2010-04-09 at 08:59 -0700, Roland Scheidegger wrote:
> > > On 09.04.2010 17:49, Keith Whitwell wrote:
> > > > On Fri, 2010-04-09 at 08:45 -0700, Roland Scheidegger wrote:
> > > >> Module: Mesa
> > > >> Branch: gallium-resources
> > > >> Commit: faf53328d1154c51d8a59513f2bfcae62272b0bf
> > > >> URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=faf53328d1154c51d8a59513f2bfcae62272b0bf
> > > >>
> > > >> Author: Roland Scheidegger <sr...@vm...>
> > > >> Date:   Fri Apr  9 17:44:24 2010 +0200
> > > >>
> > > >> gallium: fix comments for changed USAGE flags
> > > >>
> > > >> ---
> > > >>
> > > >>  src/gallium/auxiliary/util/u_simple_screen.h  |    9 +++++----
> > > >>  src/gallium/drivers/svga/svga_winsys.h        |   10 ++++------
> > > >>  src/gallium/include/pipe/p_screen.h           |    2 +-
> > > >>  src/gallium/include/state_tracker/sw_winsys.h |    2 +-
> > > >>  4 files changed, 11 insertions(+), 12 deletions(-)
> > > >>
> > > >> diff --git a/src/gallium/auxiliary/util/u_simple_screen.h b/src/gallium/auxiliary/util/u_simple_screen.h
> > > >> index 0042277..1ba59af 100644
> > > >> --- a/src/gallium/auxiliary/util/u_simple_screen.h
> > > >> +++ b/src/gallium/auxiliary/util/u_simple_screen.h
> > > >> @@ -73,9 +73,10 @@ struct pipe_winsys
> > > >>      * window systems must then implement that interface (rather than the
> > > >>      * other way around...).
> > > >>      *
> > > >> -    * usage is a bitmask of PIPE_BUFFER_USAGE_PIXEL/VERTEX/INDEX/CONSTANT. This
> > > >> -    * usage argument is only an optimization hint, not a guarantee, therefore
> > > >> -    * proper behavior must be observed in all circumstances.
> > > >> +    * usage is a bitmask of PIPE_BIND_*.
> > > >> +    * XXX is this true?
> > > >> +    * This usage argument is only an optimization hint, not a guarantee,
> > > >> +    * therefore proper behavior must be observed in all circumstances.
> > > > 
> > > > The new flags are no longer hints - they are supposed actually specify
> > > > which operations are permitted on a resource.  
> > > > 
> > > > Unfortunately I don't think this is very well enforced yet -- I intend
> > > > to add a "debug" layer to sit between state-tracker and driver, based on
> > > > the drivers/identity layer, which will check for violations of this &
> > > > other rules.
> > > 
> > > Ok, I thought this to be the case, but wasn't sure. I'll fix the comment.
> > > In the svga code, I actually couldn't figure out the usage flags when a
> > > winsys buffer is created. It looks like usage is always 0, except for
> > > queries it uses SVGA_BUFFER_USAGE_PINNED. Of course, that's not a
> > > resource but a winsys buffer, but as far as I can tell this ends up in a
> > > pb_buffer usage flag. Not sure if that's ok or supposed to be like that...
> > 
> > Jose has looked at this more recently than I have...
> 
> pb_buffer sits between pipe driver and the winsys, and needs to pass
> custom buffer flags unmodified from svga to the winsys.
> 
> SVGA_BUFFER_USAGE_PINNED is one of those usages.
> 
> PIPE_BIND_* don't matter at this level. What matters at the pipebuffer
> level is CPU/GPU READ/WRITE flags. Perhaps it might make sense to modify
> pipebuffer and its users to use pipebuffer specifc PB_BUFFER_*** flags
> instead of the gallium ones.

It's already done. Nevermind.

Jose