Re: [PATCH v5 0/3] Add option to mmap GEM buffers cached

[Paul Cercueil]

Hi Thomas,

Le dim., mai 23 2021 at 21:05:30 +0200, Thomas Zimmermann 
<tzimmermann@xxxxxxx> a écrit :
> Hi
>
> Am 23.05.21 um 19:04 schrieb Paul Cercueil:
> > V5 of my patchset which adds the option for having GEM buffers 
> > backed by
> > non-coherent memory.
> >
> > Changes from V4:
> >
> > - [2/3]:
> >      - Rename to drm_fb_cma_sync_non_coherent
> >      - Invert loops for better cache locality
> >      - Only sync BOs that have the non-coherent flag
> >      - Properly sort includes
> >      - Move to drm_fb_cma_helper.c to avoid circular dependency
>
> I'm pretty sure it's still not the right place. That would be 
> something like drm_gem_cma_atomic_helper.c, but creating a new file 
> just for a single function doesn't make sense.

drm_fb_cma_sync_non_coherent calls drm_fb_cma_* functions, so it's a 
better match than its former location (which wasn't good as it created 
a circular dependency between drm.ko and drm-kms-helper.ko).

Do you have a better idea?

> > - [3/3]:
> >      - Fix drm_atomic_get_new_plane_state() used to retrieve the old
> >        state
> >      - Use custom drm_gem_fb_create()
>
> It's often a better choice to express such differences via different 
> data structures (i.e., different instances of drm_mode_config_funcs) 
> but it's not a big deal either.

The different drm_mode_config_funcs instances already exist in 
drm_gem_framebuffer_helper.c but are static, and drm_gem_fb_create() 
and drm_gem_fb_create_with_dirty() are just tiny wrappers around 
drm_gem_fb_create_with_funcs() with the corresponding 
drm_mode_config_funcs instance. I didn't want to copy them to 
ingenic-drm-drv.c, but maybe I can export the symbols and use 
drm_gem_fb_create_with_funcs() directly?

> Please go ahaed and merge if no one objects. All patches:
>
> Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

Thanks!

Cheers,
-Paul

> Best regards
> Thomas
>
> >      - Only check damage clips and sync DMA buffers if non-coherent
> >        buffers are used
> >
> > Cheers,
> > -Paul
> >
> > Paul Cercueil (3):
> >    drm: Add support for GEM buffers backed by non-coherent memory
> >    drm: Add and export function drm_fb_cma_sync_non_coherent
> >    drm/ingenic: Add option to alloc cached GEM buffers
> >
> >   drivers/gpu/drm/drm_fb_cma_helper.c       | 46 ++++++++++++++++++
> >   drivers/gpu/drm/drm_gem_cma_helper.c      | 38 +++++++++++----
> >   drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 59 
> > +++++++++++++++++++++--
> >   drivers/gpu/drm/ingenic/ingenic-drm.h     |  1 +
> >   drivers/gpu/drm/ingenic/ingenic-ipu.c     | 21 ++++++--
> >   include/drm/drm_fb_cma_helper.h           |  4 ++
> >   include/drm/drm_gem_cma_helper.h          |  3 ++
> >   7 files changed, 156 insertions(+), 16 deletions(-)
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
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