Re: [PATCH 06/12] drm/sun4i: sun6i_mipi_dsi: Fix VBP size calculation

[Maxime Ripard]

On Thu, Sep 27, 2018 at 05:18:44PM +0530, Jagan Teki wrote:
> According to horizontal and vertical timings are defined
> per the diagram from include/drm/drm_modes.h
> 
> Back porch = [hv]total - [hv]sync_end
>
> So, update SUN6I_DSI_BASIC_SIZE0_VBP calculation as
> mode->vtotal - mode->vsync_end
> 
> Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> index 1c7e42015645..599284971ab6 100644
> --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> @@ -526,8 +526,8 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
>  	regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE0_REG,
>  		     SUN6I_DSI_BASIC_SIZE0_VSA(mode->vsync_end -
>  					       mode->vsync_start) |
> -		     SUN6I_DSI_BASIC_SIZE0_VBP(mode->vsync_start -
> -					       mode->vdisplay));
> +		     SUN6I_DSI_BASIC_SIZE0_VBP(mode->vtotal -
> +					       mode->vsync_end));

Is it purely theoretical, or did you find some source that back that?

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com