Re: [PATCH v3 4/8] drm/sun4i: dsi: Fix front vs back porch calculation

Paul Kocialkowski
2019-02-12T15:41:35Z

Hi,

On Mon, 2019-02-11 at 15:41 +0100, Maxime Ripard wrote:
> Since I always confuse the back and front porches, a few miscalculation
> slipped through. Fix them.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

Food for thoughts: everything indicates that backporch does not count
sync length for the DSI registers (while it does for TCON). So all
these changes look good!

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

Cheers,

Paul

> ---
> drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> index 506f2e8cf454..2518a0d7567c 100644
> --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> @@ -477,7 +477,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
> */
> #define HBP_PACKET_OVERHEAD 6
> hbp = max((unsigned int)HBP_PACKET_OVERHEAD,
> - (mode->hsync_start - mode->hdisplay) * Bpp - HBP_PACKET_OVERHEAD);
> + (mode->htotal - mode->hsync_end) * Bpp - HBP_PACKET_OVERHEAD);
>
> /*
> * The frontporch is set using a blanking packet (4 bytes +
> @@ -485,7 +485,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
> */
> #define HFP_PACKET_OVERHEAD 6
> hfp = max((unsigned int)HFP_PACKET_OVERHEAD,
> - (mode->htotal - mode->hsync_end) * Bpp - HFP_PACKET_OVERHEAD);
> + (mode->hsync_start - mode->hdisplay) * Bpp - HFP_PACKET_OVERHEAD);
>
> /*
> * hblk seems to be the line + porches length.
> @@ -531,8 +531,8 @@ 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));
>
> regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE1_REG,
> SUN6I_DSI_BASIC_SIZE1_VACT(mode->vdisplay) |
--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering