The horizontal and vertical back porch calculation in BSP code is simply following the Linux drm comment diagram, in include/drm/drm_modes.h which is
[hv]back porch = [hv]total - [hv]sync_end
BSP code form BPI-M64-bsp is calculating vertical back porch as (from linux-sunxi/drivers/video/sunxi/disp2/disp/de/disp_lcd.c)
timmings->ver_sync_time= panel_info->lcd_vspw; timmings->ver_back_porch= panel_info->lcd_vbp-panel_info->lcd_vspw;
vbp = panel->lcd_vbp; vspw = panel->lcd_vspw; dsi_dev[sel]->dsi_basic_size0.bits.vbp = vbp-vspw; dsi_dev[sel]->dsi_basic_size0.bits.vbp = panel->lcd_vbp - panel->lcd_vspw; => timmings->ver_back_porch + panel_info->lcd_vspw - panel_info->lcd_vspw => timmings->ver_back_porch => mode->vtotal - mode->end
Which evatually same as mode->vtotal - mode->vsync_end so fix the VBP value in SUN6I_DSI_BASIC_SIZE0_VBP
On the information note, existing SUN6I_DSI_BASIC_SIZE0_VSA is proper value.
Signed-off-by: Jagan Teki jagan@amarulasolutions.com --- 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 318994cd1b85..d70a8c43a4b8 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));
regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE1_REG, SUN6I_DSI_BASIC_SIZE1_VACT(mode->vdisplay) |