From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender-op-o11.zoho.in (sender-op-o11.zoho.in [103.117.158.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3ECEE3EB0E6 for ; Fri, 26 Jun 2026 09:51:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=103.117.158.11 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782467525; cv=pass; b=FEUNBYj3WaMdji1xGD/VPWRInQ1QvmKX7QpOZlw6kwIe9KALuAXIFpSrtBsJm/EX/dIOm2011pXZG/wmz5J0mfuRBxwxXyBgfwCqhCfV38YfVd1C4nYnyExJKpNmVP5yfTubAHQBRgrzqEoUSWTtn8MEQSa/f75T6qighc5X7zI= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782467525; c=relaxed/simple; bh=VV1ECIiTGBJeT4pimv/oANtMZNOmdEG0BsS8lZxXOYs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hmp/jAttefpgp7sE5u4G7tmQhgmLzY6w2GS++aGRyi1ZmbO4cpXRYHxXRmmBhEnStTl7bgHjzPbPFNUiiT5VFg/Y4krdGigDd98etH3Z4+zTh+ittd8AGVmrWQnT3hkKCIwkRnRju6r6ULUS+ByxYSfwLjppgGyeuc5O3oSj0IA= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=rebhu.com; spf=pass smtp.mailfrom=rebhu.com; dkim=pass (1024-bit key) header.d=rebhu.com header.i=shubham@rebhu.com header.b=rgjH7fgq; arc=pass smtp.client-ip=103.117.158.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=rebhu.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rebhu.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=rebhu.com header.i=shubham@rebhu.com header.b="rgjH7fgq" ARC-Seal: i=1; a=rsa-sha256; t=1782467420; cv=none; d=zohomail.in; s=zohoarc; b=RmUS6VC7km4sAsheGaE+ETBO5oS5aEH3fyaG7G5XXqDm6F/nVQXeqA1+ozTMeVgDMeWJLnCpoXpafGaTvClsKckdqSQvPyYAWyPKqg9sALGq5vR5bWvqPRiCrugMYQgX7eqn89vVD4mYbsajEg4UgOFzQ3peVPwGd48hXs7g+PI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.in; s=zohoarc; t=1782467420; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=sET9CEszVQFsTQEBjINbwDd749FE6ul7+R4eIg2DXlM=; b=H0ln0DFzGyDl1PwJVQeaqazdV4RPBFG94KffCC5PSOsSHdNJA3xdkNF86TY1PlzeYO0q9gEsKiu2sXhUPgVWtaHdG2cpZB5GST/zMRVfwnxzNxNpFolNbc2y5RiXfc/tqKr+G3WYG/p7lF8LEEKUsiyKdbCBp/f0CbiXpZ5wz3g= ARC-Authentication-Results: i=1; mx.zohomail.in; dkim=pass header.i=rebhu.com; spf=pass smtp.mailfrom=shubham@rebhu.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1782467420; s=zmail; d=rebhu.com; i=shubham@rebhu.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=sET9CEszVQFsTQEBjINbwDd749FE6ul7+R4eIg2DXlM=; b=rgjH7fgq2WWXDhMRgQ7nf556xTWh9TOcZXvObvzfQS/RHC/8i47lyXDxJoWnCtlr JcEgRfDQvSj+iRbzKGAVR1BCp3Q/oYfzoZ/zdAzMKHWWprmq+yURG0Aw6G0yTEMkeAZ 6AXj2FxvOsFtLsTFwWnWOU6ikQbtdLBdcvC77Jzk= Received: by mx.zoho.in with SMTPS id 1782467418005855.6222380842893; Fri, 26 Jun 2026 15:20:18 +0530 (IST) From: Shubham To: tomi.valkeinen@ideasonboard.com Cc: a-bhatia1@ti.com, afd@ti.com, airlied@gmail.com, aradhya.bhatia@linux.dev, conor+dt@kernel.org, devarsht@ti.com, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, j-choudhary@ti.com, krzk+dt@kernel.org, lee@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, louis.chauvet@bootlin.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, nm@ti.com, robertcnelson@gmail.com, robh@kernel.org, s-jain1@ti.com, simona@ffwll.ch, tzimmermann@suse.de, vigneshr@ti.com Subject: Re: [PATCH v3 00/15] drm/tidss: Add BeagleY-AI display support (and some more) Date: Fri, 26 Jun 2026 15:19:56 +0530 Message-ID: <20260626094956.243978-1-shubham@rebhu.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260529-beagley-ai-display-v3-0-7fefdc5d1adf@ideasonboard.com> References: <20260529-beagley-ai-display-v3-0-7fefdc5d1adf@ideasonboard.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-ZohoMailClient: External Hi Tomi, A big update on the Raspberry Pi Touch Display 2 (5-inch, native ILI9881C MIPI-DSI, 720x1280, 2 lanes) bring-up on BeagleY-AI (AM67A/J722S), still on Robert's v7.0.x-arm64-k3 tree (7.0.11-arm64-k3-r20): tidss + cdns-dsi + cdns-dphy, DSS = ti,am62p-dss (dispc_am625_feats). The earlier "tidss comes up before the DSI bridge is added" problem is resolved (cdns-dsi now adds its input bridge in probe, so tidss attaches it), and after fixing two more issues the panel is now alive -- but I'm stuck on one last step and would value your read. What is now confirmed working ----------------------------- - DSI-1 connector is created, tidss initializes, no probe errors, nothing left in /sys/kernel/debug/devices_deferred. - The panel is ALIVE and initialized: a DCS read of GET_POWER_MODE (0x0A) returns 0x9c (booster on, sleep-out, display-on). So the LP command path over the cdns works and the ILI9881C processed its init sequence. - cdns-dsi looks healthy while a test pattern streams: MCTL_MAIN_STS = 0x0000000F (PLL_LOCKED + CLK_LANE_RDY + DATA_LANE_RDY 0/1) MCTL_DPHY_ERR = 0x00000000 (no D-PHY errors) VID_MODE_STS = 0x00000001 (VSG_RUNNING, no error bits) MCTL_LANE_STS -> clock lane in HS VID_MAIN_CTL = 0x80A0FE00 (RGB888, packed-pixel DT 0x3E) VID_HSIZE2 hact = 2160 (720*3), VID_VSIZE2 vact = 1280 cdns-dphy PLL locks (no "Failed to lock PLL"). - The DSS is scanning out: modetest -M tidss -s @:720x1280 -v -> steady 60.01 Hz. (For reference, the two fixes that got the panel this far were: nesting the DSS port@1 under the controller's "ports" node in my overlay, and correcting the BeagleY-AI MIPI mux OE polarity -- it is active-low, and the data-lane mux had been left disabled while i2c still worked through a separate path.) The problem: cdns data lanes never transmit ------------------------------------------- Sampling MCTL_LANE_STS 20000 times while the pattern is actively streaming (modetest -v at 60 Hz, from a second session): DATA0 states: {'IDLE': 20000} DATA1 states: {'IDLE': 20000} So the clock lane is in HS and the VSG reports "running", but the data lanes are 100% IDLE -- the cdns is in video mode yet never emits pixel packets. The DSS VP does not appear to feed the cdns DPI input even though the VP timing generator runs at 60 Hz, and the panel (correctly initialized) just shows backlight, no image. What I have ruled out --------------------- - Videoport selection: I tried the DSI on DSS port@1 (VP2 = DISPC_VP_DPI) and on DSS port@0 (VP1 = DISPC_VP_INTERNAL). Identical result, data lanes IDLE in both. - tidss correctly treats the cdns as internal: the bridge of_node compatible "ti,j721e-dsi" is in tidss_internal_bridge_compatibles[], so dpi_output is false and it does not touch ti,am625-dss-dpi0-clk-ctrl for this videoport. - Overlay/graph: cdns DSI_OUTPUT_PORT=0 (panel) / DSI_INPUT_PORT=1 (DSS) wired accordingly; panel attaches; no -ENODEV; VID timing is correct. Questions --------- 1. On AM67A/J722S, what internally connects a DSS video port's DPI to the cdns-dsi DPI input, and is there a clock/enable/routing step (beyond the DT graph and dpi0-clk-ctrl, which tidss skips for the internal path) required for the DSS to actually feed the cdns? 2. Which DSS VP is wired to the internal DSI on this SoC (VP1/INTERNAL vs VP2/DPI), and does the DISPC_VP_INTERNAL path need any handling that the DISPC_VP_DPI path does not get? 3. Any reason the cdns VSG would report VSG_RUNNING with the clock lane in HS and both data lanes "ready", yet never drive the data lanes (no pixel packets) while the DSS VP is visibly scanning at 60 Hz? I'm happy to share the full overlay, dmesg and register dumps, and to test patches. Thanks, Shubham