From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67868C4707F for ; Tue, 5 Apr 2022 20:56:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379872AbiDEUyP (ORCPT ); Tue, 5 Apr 2022 16:54:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230042AbiDEJsy (ORCPT ); Tue, 5 Apr 2022 05:48:54 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96335DF35; Tue, 5 Apr 2022 02:38:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3E093B818F3; Tue, 5 Apr 2022 09:38:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82CC5C385A2; Tue, 5 Apr 2022 09:38:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649151534; bh=FEhFHiceQxymASY0Cnhc+plWks288D4lT8BKESj8hAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PTmxC0P8LrGBEpQvyTQ6xgNIiMY8N8we4Sahk7urP1E1dA7A5iM6leXUge7Jn8VC+ uMBkneddj2u4GiWixjSVTXk6rLbVZ3g7SDbCj4uF79QkdPLF+xnQKESgckZFyLPiW4 5SNmgeGW55TCMWmW9sJquUNovCvEE4DL/qj6RKj4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Biju Das , Kieran Bingham , Neil Armstrong , Robert Foss , Sasha Levin Subject: [PATCH 5.15 449/913] drm/bridge: dw-hdmi: use safe format when first in bridge chain Date: Tue, 5 Apr 2022 09:25:11 +0200 Message-Id: <20220405070353.306917779@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070339.801210740@linuxfoundation.org> References: <20220405070339.801210740@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Neil Armstrong [ Upstream commit 1528038385c0a706aac9ac165eeb24044fef6825 ] 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 Bisected-by: Kieran Bingham Tested-by: Kieran Bingham Fixes: 6c3c719936da ("drm/bridge: synopsys: dw-hdmi: add bus format negociation") Signed-off-by: Neil Armstrong [narmstrong: add proper fixes commit] Reviewed-by: Robert Foss Link: https://patchwork.freedesktop.org/patch/msgid/20220204143337.89221-1-narmstrong@baylibre.com Signed-off-by: Sasha Levin --- 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 e1211a5b334b..25d58dcfc87e 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; -- 2.34.1