From: Jiri Vanek jirivanek1@gmail.com
[ Upstream commit 993a87917c2af59efb0ee1ce43c878ca8790ba1c ]
Use the same PCLK divide option (divide DSI clock to generate pixel clock) which is set to LVDS Configuration Register (LVCFG) also for a VSync delay calculation. Without this change an auxiliary variable could underflow during the calculation for some dual-link LVDS panels and then calculated VSync delay is wrong. This leads to a shifted picture on a panel.
Tested-by: Jiri Vanek jirivanek1@gmail.com Signed-off-by: Jiri Vanek jirivanek1@gmail.com Reviewed-by: Vinay Simha BN simhavcs@gmail.com Signed-off-by: Robert Foss robert.foss@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20220615222221.1501-3-jirivane... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/bridge/tc358775.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/tc358775.c b/drivers/gpu/drm/bridge/tc358775.c index 62a7ef352daa..dd18be95207b 100644 --- a/drivers/gpu/drm/bridge/tc358775.c +++ b/drivers/gpu/drm/bridge/tc358775.c @@ -429,7 +429,7 @@ static void tc_bridge_enable(struct drm_bridge *bridge) val = TC358775_VPCTRL_MSF(1);
dsiclk = mode->crtc_clock * 3 * tc->bpc / tc->num_dsi_lanes / 1000; - clkdiv = dsiclk / DIVIDE_BY_3 * tc->lvds_link; + clkdiv = dsiclk / (tc->lvds_link == DUAL_LINK ? DIVIDE_BY_6 : DIVIDE_BY_3); byteclk = dsiclk / 4; t1 = hactive * (tc->bpc * 3 / 8) / tc->num_dsi_lanes; t2 = ((100000 / clkdiv)) * (hactive + hback_porch + hsync_len + hfront_porch) / 1000;