Re: [PATCH v3 6/8] drm/sun4i: dsi: Rework a bit the hblk calculation

[Paul Kocialkowski <paul.kocialkowski@bootlin.com>]

Hi,

On Mon, 2019-02-11 at 15:41 +0100, Maxime Ripard wrote:
> It turns out that the hblk calculation actually follows a similar pattern
> than the other packets. Rework a bit the calculation and add a comment.

This looks consistent with what the BSP is doing for video mode.

Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>

Cheers,

Paul

> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>  drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> index 8e6392831e9d..e0288e7dc64e 100644
> --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> @@ -488,9 +488,13 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
>  		  (mode->hsync_start - mode->hdisplay) * Bpp - HFP_PACKET_OVERHEAD);
>  
>  	/*
> -	 * hblk seems to be the line + porches length.
> +	 * The blanking is set using a sync event (4 bytes) and a
> +	 * blanking packet (4 bytes + payload + 2 bytes). Its minimal
> +	 * size is therefore 10 bytes.
>  	 */
> -	hblk = mode->htotal * Bpp - hsa;
> +#define HBLK_PACKET_OVERHEAD	10
> +	hblk = max((unsigned int)HBLK_PACKET_OVERHEAD,
> +		   (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp - HBLK_PACKET_OVERHEAD);
> 
>  	/*
>  	 * And I'm not entirely sure what vblk is about. The driver in
-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com


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