Re: [PATCH 15/21] drm/rcar-du: Use GEM CMA object functions

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Thomas,

On Mon, May 25, 2020 at 02:49:46PM +0200, Thomas Zimmermann wrote:
> Am 22.05.20 um 22:12 schrieb Laurent Pinchart:
> > On Fri, May 22, 2020 at 03:52:40PM +0200, Thomas Zimmermann wrote:
> >> The rcar-du driver uses the default implementation for CMA functions;
> >> except for the .dumb_create callback. The __DRM_GEM_CMA_DRIVER_OPS macro
> >> now sets these defaults and .dumb_create in struct drm_driver. All
> >> remaining operations are provided by CMA GEM object functions.
> >>
> >> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> >> ---
> >>  drivers/gpu/drm/rcar-du/rcar_du_drv.c | 11 +----------
> >>  1 file changed, 1 insertion(+), 10 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.c b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> >> index 3e67cf70f0402..3728038cec1d1 100644
> >> --- a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> >> +++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> >> @@ -476,16 +476,7 @@ DEFINE_DRM_GEM_CMA_FOPS(rcar_du_fops);
> >>  
> >>  static struct drm_driver rcar_du_driver = {
> >>  	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
> >> -	.gem_free_object_unlocked = drm_gem_cma_free_object,
> >> -	.gem_vm_ops		= &drm_gem_cma_vm_ops,
> >> -	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
> >> -	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
> >> -	.gem_prime_get_sg_table	= drm_gem_cma_prime_get_sg_table,
> >> -	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
> >> -	.gem_prime_vmap		= drm_gem_cma_prime_vmap,
> >> -	.gem_prime_vunmap	= drm_gem_cma_prime_vunmap,
> >> -	.gem_prime_mmap		= drm_gem_cma_prime_mmap,
> >> -	.dumb_create		= rcar_du_dumb_create,
> >> +	__DRM_GEM_CMA_DRIVER_OPS(rcar_du_dumb_create),
> > 
> > Your __DRM_GEM_CMA_DRIVER_OPS is defined as
> > 
> > #define __DRM_GEM_CMA_DRIVER_OPS(__dumb_create) \
> >         .gem_create_object      = drm_cma_gem_create_object_default_funcs, \
> >         .dumb_create            = (__dumb_create), \
> >         .prime_handle_to_fd     = drm_gem_prime_handle_to_fd, \
> >         .prime_fd_to_handle     = drm_gem_prime_fd_to_handle, \
> >         .gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table_vmap, \
> >         .gem_prime_mmap         = drm_gem_prime_mmap
> > 
> > The patch thus introduces several changes:
> > 
> > - drm_gem_cma_prime_import_sg_table_vmap() is used instead of
> >   drm_gem_cma_prime_import_sg_table() combined with .gem_prime_vmap()
> >   and .gem_prime_vunmap(). I believe that's fine, but splitting that
> >   change in a separate commit, or at the very least explaining it in
> >   details in the commit message, would make review easier.
> > 
> > - .gem_create_object() is now set. That seems to be OK, but I'm not sure
> >   to grasp all the implications. This should also be explained in the
> >   commit message, and ideally split to a separate patch.
> 
> That's relevant during object creation and sets the object functions.
> See one of my other replies for how this can go away after all CMA
> drivers have been updated to GEM object functions.

I don't dispute that's fine, but I think it should really be explained
in the commit message, and ideally split to a separate patch.

> > - drm_gem_cma_prime_mmap() is replaced with drm_gem_prime_mmap(). Same
> >   comments :-)
> 
> I relied on the aspeed driver to be correct. After Sam's comment on
> that, I read the code once again several times. The original
> implementation clears VM_PFNMAP. And I cannot find that code any longer.
> Going back to the original function might be better.
> 
> > This patch hides way too many changes in what is documented as just
> > innocent refactoring. It seems other drivers are affected too.
> 
> Could you test the patchset? I don't have the HW.

Kieran has beaten me to it :-)

> >>  	.fops			= &rcar_du_fops,
> >>  	.name			= "rcar-du",
> >>  	.desc			= "Renesas R-Car Display Unit",

-- 
Regards,

Laurent Pinchart
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