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

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Submitter Maxime Ripard
Date Feb. 11, 2019, 2:41 p.m.
Message ID <d79a21b09847579ce907212a59737af21a729dd0.1549896081.git-series.maxime.ripard@bootlin.com>
Download mbox | patch
Permalink /patch/723001/
State New
Headers show

Comments

Maxime Ripard - Feb. 11, 2019, 2:41 p.m.
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.

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(-)
Paul Kocialkowski - Feb. 13, 2019, 2:41 p.m.
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

Patch

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