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

Paul Kocialkowski
2019-02-13T14:42:10Z

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