From mboxrd@z Thu Jan 1 00:00:00 1970 From: jagan@amarulasolutions.com (Jagan Teki) Date: Thu, 27 Sep 2018 17:18:46 +0530 Subject: [PATCH 08/12] drm/sun4i: sun6i_mipi_dsi: Refactor vertical video start delay In-Reply-To: <20180927114850.24565-1-jagan@amarulasolutions.com> References: <20180927114850.24565-1-jagan@amarulasolutions.com> Message-ID: <20180927114850.24565-9-jagan@amarulasolutions.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Accordingly to BPI-M64-bsp DE DSI code Video start delay can be computed by subtracting total vertical timing with front porch timing and with adding 1 delay line for TCON. This patch simply add the start_delay logic from BPI-M64-bsp, w/o this new computation, the DSI on A64 encounter vblank time out. [CRTC:36:crtc-0] vblank wait timed out Signed-off-by: Jagan Teki --- drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c index 9918fdb990ff..217db74c6dc3 100644 --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c @@ -358,7 +358,17 @@ static void sun6i_dsi_inst_init(struct sun6i_dsi *dsi, static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi, struct drm_display_mode *mode) { - return mode->vtotal - (mode->vsync_end - mode->vdisplay) + 1; + u32 vfp = mode->vsync_start - mode->vdisplay; + u32 start_delay; + + start_delay = mode->vtotal - vfp + 1; + if (start_delay > mode->vtotal) + start_delay -= mode->vtotal; + + if (!start_delay) + start_delay = 1; + + return start_delay; } static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi, -- 2.18.0.321.gffc6fa0e3