Re: [PATCH v4 1/1] drm/fb-helper: implement ioctl FBIO_WAITFORVSYNC

[Stefan Lengfeld]

Hi Maxime,

On Tue, Feb 28, 2017 at 04:36:51PM +0100, Maxime Ripard wrote:
> Implement legacy framebuffer ioctl FBIO_WAITFORVSYNC in the generic
> framebuffer emulation driver. Legacy framebuffer users like non kms/drm
> based OpenGL(ES)/EGL implementations may require the ioctl to
> synchronize drawing or buffer flip for double buffering. It is tested on
> the i.MX6.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> Tested-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/drm_fb_helper.c | 68 ++++++++++++++++++++++++++++++++++-
>  include/drm/drm_fb_helper.h     | 12 +++++-
>  2 files changed, 79 insertions(+), 1 deletion(-)

I have tested the current HEAD of drm-misc-next. It includes this patch
and the patch ("drm/fb-helper: Add multi buffer support for cma fbdev").
On my i.MX6 board with HDMI output both patches work as advertised.
Multi-buffering with ioctls FBIO_WAITFORVSYNC and FBIOPAN_DISPLAY is
possible.

Kind Regards
    Stefan Lengfeld