[Mesa-dev] [PATCH] gbm: Add a flag to enable creation of rotated scanout buffers (v2)

[Vivek Kasireddy]

On Thu, 5 Nov 2015 15:34:27 +0900
Michel Dänzer <michel at daenzer.net> wrote:

> On 05.11.2015 11:32, Vivek Kasireddy wrote:
> > For certain platforms that support rotated scanout buffers,
> > currently, there is no way to create them with the GBM DRI
> > interface. This flag will instruct the DRI driver to create the
> > buffer by setting additional requirements such as tiling mode.
> > 
> > v2: Reserve a bit per angle. (Ville and Michel)
> > 
> > Cc: Michel Danzer <michel at daenzer.net>
> > Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy at intel.com>
> > ---
> >  include/GL/internal/dri_interface.h |  3 +++
> >  src/gbm/backends/dri/gbm_dri.c      | 19 +++++++++++++++++--
> >  src/gbm/main/gbm.h                  |  7 +++++++
> >  3 files changed, 27 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/GL/internal/dri_interface.h
> > b/include/GL/internal/dri_interface.h index 6bbd3fa..cd1bf62 100644
> > --- a/include/GL/internal/dri_interface.h
> > +++ b/include/GL/internal/dri_interface.h
> > @@ -1100,6 +1100,9 @@ struct __DRIdri2ExtensionRec {
> >  #define __DRI_IMAGE_USE_SCANOUT		0x0002
> >  #define __DRI_IMAGE_USE_CURSOR		0x0004 /* Depricated
> > */ #define __DRI_IMAGE_USE_LINEAR		0x0008
> > +#define __DRI_IMAGE_USE_ROTATION_90	0x0010
> > +#define __DRI_IMAGE_USE_ROTATION_180	0x0020
> > +#define __DRI_IMAGE_USE_ROTATION_270	0x0040
> >  
> >  
> >  /**
> 
> I still think the dri_interface.h change should be a separate patch.
> 
> 
> > diff --git a/src/gbm/backends/dri/gbm_dri.c
> > b/src/gbm/backends/dri/gbm_dri.c index 57cdeac..a997946 100644
> > --- a/src/gbm/backends/dri/gbm_dri.c
> > +++ b/src/gbm/backends/dri/gbm_dri.c
> > @@ -539,7 +539,8 @@ gbm_dri_is_format_supported(struct gbm_device
> > *gbm, break;
> >     case GBM_BO_FORMAT_ARGB8888:
> >     case GBM_FORMAT_ARGB8888:
> > -      if (usage & GBM_BO_USE_SCANOUT)
> > +      if (usage & (GBM_BO_USE_SCANOUT | GBM_BO_USE_ROTATION_90 |
> > +          GBM_BO_USE_ROTATION_180 | GBM_BO_USE_ROTATION_270))
> >           return 0;
> >        break;
> >     default:
> 
> If you stick to this approach (see below), I suggest adding a
> GBM_BO_USE_SCANOUT_ANY define which combines all
> GBM_BO_USE_SCANOUT(_ROTATION_*) values, to make these checks less
> cumbersome.
> 
> 
> > diff --git a/src/gbm/main/gbm.h b/src/gbm/main/gbm.h
> > index 8db2153..b200ca6 100644
> > --- a/src/gbm/main/gbm.h
> > +++ b/src/gbm/main/gbm.h
> > @@ -214,6 +214,13 @@ enum gbm_bo_flags {
> >      * Buffer is linear, i.e. not tiled.
> >      */
> >     GBM_BO_USE_LINEAR = (1 << 4),
> > +   /**
> > +    * Buffer would be rotated and some platforms have additional
> > tiling
> > +    * requirements for rotated scanout buffers.
> > +    */
> > +   GBM_BO_USE_ROTATION_90 = (1 << 5),
> > +   GBM_BO_USE_ROTATION_180 = (1 << 6),
> > +   GBM_BO_USE_ROTATION_270 = (1 << 7),
> >  };
> >  
> >  int
> > 
> 
> With this approach, these should be named
> GBM_BO_USE_SCANOUT_ROTATION_* to make it clearer that they are
> alternatives to GBM_BO_USE_SCANOUT.
> 
> One issue with this approach is: What happens if several
> GBM_BO_USE_SCANOUT_ROTATION_* flags are set, and the hardware has
> conflicting requirements for different rotation angles?

Hi Michel,
If multiple GBM_BO_USE_SCANOUT_ROTATION_* flags are set and if the
hardware has conflicting requirements for different rotation angles, I
think it should be flagged as an error not in GBM but perhaps in the
DRI driver as it is expected to figure out the requirements for
rotation.

Thanks and Regards,
Vivek

> 
>