Messages in this thread Patch in this message | | | From | Neil Armstrong <> | Subject | [PATCH v3] drm/bridge: dw-hdmi: use safe format when first in bridge chain | Date | Fri, 4 Feb 2022 15:33:37 +0100 |
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When the dw-hdmi bridge is in first place of the bridge chain, this means there is no way to select an input format of the dw-hdmi HW component.
Since introduction of display-connector, negotiation was broken since the dw-hdmi negotiation code only worked when the dw-hdmi bridge was in last position of the bridge chain or behind another bridge also supporting input & output format negotiation.
Commit 7cd70656d128 ("drm/bridge: display-connector: implement bus fmts callbacks") was introduced to make negotiation work again by making display-connector act as a pass-through concerning input & output format negotiation.
But in the case where the dw-hdmi is single in the bridge chain, for example on Renesas SoCs, with the display-connector bridge the dw-hdmi is no more single, breaking output format.
Reported-by: Biju Das <biju.das.jz@bp.renesas.com> Bisected-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> Tested-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> Fixes: 7cd70656d128 ("drm/bridge: display-connector: implement bus fmts callbacks"). Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Reviewed-by: Robert Foss <robert.foss@linaro.org> --- Changes since v2: - Add rob's r-b - Fix invalid Fixes commit hash
Changes since v1: - Remove bad fix in dw_hdmi_bridge_atomic_get_input_bus_fmts - Fix typos in commit message
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index 54d8fdad395f..97cdc61b57f6 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c @@ -2551,8 +2551,9 @@ static u32 *dw_hdmi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge, if (!output_fmts) return NULL; - /* If dw-hdmi is the only bridge, avoid negociating with ourselves */ - if (list_is_singular(&bridge->encoder->bridge_chain)) { + /* If dw-hdmi is the first or only bridge, avoid negociating with ourselves */ + if (list_is_singular(&bridge->encoder->bridge_chain) || + list_is_first(&bridge->chain_node, &bridge->encoder->bridge_chain)) { *num_output_fmts = 1; output_fmts[0] = MEDIA_BUS_FMT_FIXED; -- 2.25.1
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