[PATCHv1] drm/omap: get fbdev working for manually updated display

[Laurent Pinchart]

On Sat, May 01, 2021 at 10:00:50PM +0200, Sebastian Reichel wrote:
> Running a legacy application, which directly uses /dev/fb0
> currently results in display not being refreshed when the
> application mmaps the memory instead of calling write().
> 
> Deferred IO support will also schedule dirty_work with the
> damage collected from the mmap page writes and thus gets
> some more legacy applications working.
> 
> Delay frequency settings have been taken over from
> drm_fb_helper_generic_probe().
> 
> Reported-by: Carl Philipp Klemm <philipp at uvos.xyz>
> Tested-by: Carl Philipp Klemm <philipp at uvos.xyz>
> Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.com>
> ---
> Hi,
> 
> I still need to fix my Droid 4, so I only compile tested this
> myself.
> 
> -- Sebastian
> ---
>  drivers/gpu/drm/omapdrm/omap_fbdev.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> index 42eac6ad12bd..fc3897d2d7cc 100644
> --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> @@ -87,6 +87,11 @@ static const struct fb_ops omap_fb_ops = {
>  	.fb_imageblit = drm_fb_helper_sys_imageblit,
>  };
>  
> +static struct fb_deferred_io omap_fb_defio = {
> +	.delay		= HZ / 20,
> +	.deferred_io	= drm_fb_helper_deferred_io,
> +};

Wish this could be const :-S

> +
>  static int omap_fbdev_create(struct drm_fb_helper *helper,
>  		struct drm_fb_helper_surface_size *sizes)
>  {
> @@ -176,6 +181,9 @@ static int omap_fbdev_create(struct drm_fb_helper *helper,
>  
>  	drm_fb_helper_fill_info(fbi, helper, sizes);
>  
> +	fbi->fbdefio = &omap_fb_defio;
> +	fb_deferred_io_init(fbi);
> +

This looks good to me. Trusting the Tested-by,

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

>  	dev->mode_config.fb_base = dma_addr;
>  
>  	fbi->screen_buffer = omap_gem_vaddr(fbdev->bo);

-- 
Regards,

Laurent Pinchart