From ed761e0693950fcb4f6b0f60387a3961b972adf3 Mon Sep 17 00:00:00 2001 From: Leonardo Costa Date: Mon, 6 Jul 2026 10:24:17 -0300 Subject: [PATCH] drm/bridge: tc358768: Enforce input bus flags via atomic_check The tc358768 declares static bridge timings requiring pixel data to be sampled on the positive clock edge. However, the DRM core default propagation simply copies the output-side bus flags, coming from the next bridge, connector or panel, to the input side. If the propagated flags are incompatible with the bridge ones, the data is wrongly sampled, typically resulting in visual artifacts on the panel. Implement the atomic_check hook, replacing the mutually exclusive mode_fixup, and set the bridge state input bus flags to the ones required by the tc358768. The sync polarity defaulting previously done in mode_fixup is carried over into atomic_check unchanged. Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver") Cc: stable@vger.kernel.org Signed-off-by: Leonardo Costa Reviewed-by: Francesco Dolcini Reviewed-by: Swamil Jain Reviewed-by: Luca Ceresoli Link: https://patch.msgid.link/20260706132440.1594239-1-leoreis.costa@gmail.com Signed-off-by: Luca Ceresoli --- drivers/gpu/drm/bridge/tc358768.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index d1fc6af37cc5..19b43efcf93f 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -1263,10 +1263,13 @@ tc358768_atomic_get_input_bus_fmts(struct drm_bridge *bridge, return input_fmts; } -static bool tc358768_mode_fixup(struct drm_bridge *bridge, - const struct drm_display_mode *mode, - struct drm_display_mode *adjusted_mode) +static int tc358768_bridge_atomic_check(struct drm_bridge *bridge, + struct drm_bridge_state *bridge_state, + struct drm_crtc_state *crtc_state, + struct drm_connector_state *conn_state) { + struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode; + /* Default to positive sync */ if (!(adjusted_mode->flags & @@ -1277,13 +1280,15 @@ static bool tc358768_mode_fixup(struct drm_bridge *bridge, (DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_NVSYNC))) adjusted_mode->flags |= DRM_MODE_FLAG_PVSYNC; - return true; + bridge_state->input_bus_cfg.flags = bridge->timings->input_bus_flags; + + return 0; } static const struct drm_bridge_funcs tc358768_bridge_funcs = { .attach = tc358768_bridge_attach, .mode_valid = tc358768_bridge_mode_valid, - .mode_fixup = tc358768_mode_fixup, + .atomic_check = tc358768_bridge_atomic_check, .atomic_pre_enable = tc358768_bridge_atomic_pre_enable, .atomic_enable = tc358768_bridge_atomic_enable, .atomic_disable = tc358768_bridge_atomic_disable,