From 4af021a977735420e8fe18d64bef18ad0608d981 Mon Sep 17 00:00:00 2001 From: Sudarshan Shetty Date: Wed, 27 May 2026 14:27:35 +0530 Subject: [PATCH] drm: bridge: ti-sn65dsi83: Remove NO_HFP and NO_HBP mode flags for LVDS stability The current DSI mode configuration disables horizontal front porch (HFP) and back porch (HBP) transmission using MIPI_DSI_MODE_VIDEO_NO_HFP and MIPI_DSI_MODE_VIDEO_NO_HBP. However, the SN65DSI83/84 bridge relies on receiving full horizontal timing information over DSI in order to correctly reconstruct the LVDS output timings. When HFP and HBP are not transmitted, the bridge cannot recreate the required timing parameters, resulting in unstable or missing display output on some panels. The SN65DSI84 datasheet also describes transmission of complete horizontal timing information as part of the DSI video stream. Remove MIPI_DSI_MODE_VIDEO_NO_HFP and MIPI_DSI_MODE_VIDEO_NO_HBP so that HFP and HBP timing information is transmitted to the bridge. Reference: SN65DSI84 Datasheet, Section 7.4.7 (page 20): https://www.ti.com/lit/ds/symlink/sn65dsi84.pdf Tested-by: Luca Ceresoli Tested-by: Alexander Stein Signed-off-by: Sudarshan Shetty Reviewed-by: Luca Ceresoli Link: https://patch.msgid.link/20260527085736.920390-2-tessolveupstream@gmail.com [Luca: cleaned up datasheet URL] Signed-off-by: Luca Ceresoli --- drivers/gpu/drm/bridge/ti-sn65dsi83.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c index 42b451432bbb..c03ff1ea9df8 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c @@ -977,7 +977,6 @@ static int sn65dsi83_host_attach(struct sn65dsi83 *ctx) dsi->lanes = dsi_lanes; dsi->format = MIPI_DSI_FMT_RGB888; dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST | - MIPI_DSI_MODE_VIDEO_NO_HFP | MIPI_DSI_MODE_VIDEO_NO_HBP | MIPI_DSI_MODE_VIDEO_NO_HSA | MIPI_DSI_MODE_NO_EOT_PACKET; ret = devm_mipi_dsi_attach(dev, dsi);