[PATCH 0/2] drm: CMA fbdev stride adjustment

[Daniel Vetter]

On Wed, Aug 12, 2015 at 03:52:12PM -0500, Rob Herring wrote:
> I'm working on a DRM driver for PXA1928. Other than a stride alignment 
> requirement of 16 bytes, I have no other reason not to use fbdev_cma. 
> While I can adjust the stride for drm_gem_cma_dumb_create, I cannot do 
> the same for drm_fbdev_cma_create without duplicating a bunch of code. 
> This series allows fbdev_cma users to override the fb_probe function, so 
> the stride can be adjusted.
> 
> It appears to me that rcar-du has a bug that it doesn't handle alignment 
> requirements for this case as well. Probably just getting lucky with 
> tested resolutions/bpp.
> 
> Also, AFAICT the Rockchip driver has no real reason to use a custom GEM 
> allocator instead of the CMA one. It sets the DMA_ATTR_NO_KERNEL_MAPPING 
> DMA attr, but that could easily be supported by the CMA allocator.

I think it'd be easier to review this with the driver at hand. That's also
generally the requirement for merging new code - it needs an in-kernel
user.
-Daniel

> 
> Rob
> 
> Rob Herring (2):
>   drm/cma: allow custom fb helper functions
>   drm/cma: allow adjusting the pitch for CMA fbdev
> 
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c |  2 +-
>  drivers/gpu/drm/drm_fb_cma_helper.c          | 13 ++++++++++---
>  drivers/gpu/drm/imx/imx-drm-core.c           |  2 +-
>  drivers/gpu/drm/rcar-du/rcar_du_kms.c        |  3 ++-
>  drivers/gpu/drm/sti/sti_drm_drv.c            |  2 +-
>  drivers/gpu/drm/tilcdc/tilcdc_drv.c          |  2 +-
>  include/drm/drm_fb_cma_helper.h              |  7 +++++++
>  include/drm/drm_fb_helper.h                  |  1 +
>  8 files changed, 24 insertions(+), 8 deletions(-)
> 
> -- 
> 2.1.4
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch