From nobody Thu Apr 2 18:47:54 2026 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 31CF13B7741 for ; Fri, 27 Mar 2026 10:22:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774606960; cv=none; b=Aexw3QRK3oOL8dz7UqCA8SGGHlXTWz/Td+EArS82qrY0149lQ5tiqSaRjwwjFCNVrNjnGXl2f0VVJ7YVR663rkx5S3ogzCQV7r5IzBcXMiv872dDMet0/NkRZCtsAy1qCjWAjxXImthBqZKt2Bn8Ralgci1qFzQL36NUc17u/7M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774606960; c=relaxed/simple; bh=qDgOvHrPx5VBCjCyaz4snC9nowUJ1uQTs9EWYBT2EmM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lgkeuKOpNzQcMe/785HW3nFEGwSf5TlL44pwC40n1XsEx/C8XH4fZ8Up7XozE4fGDZxjzIrVzhKrtmxU7LYYA3AsSLHlJor+ilzznPwmciG8RF+Nhv0teHCUmgjDVTNf1/pvGskg2Puye0QD0/iaL/D1pb9IE/1WbocXpiawGzM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=oxaeOqAK; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="oxaeOqAK" Received: from [127.0.1.1] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 2B0752F85; Fri, 27 Mar 2026 11:21:11 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1774606871; bh=qDgOvHrPx5VBCjCyaz4snC9nowUJ1uQTs9EWYBT2EmM=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=oxaeOqAKnSjzuZdPtXjnImwUa4GyysR+oRP23w0e+kVgt6UyJMiANttyWe2K9+Nq4 kcXko+ieuDtOHVzgWRge5cqSSyjtqNtmM4wXc5Ghe9l/SjcXxwaqgRHlB633cUSsQ7 Z87ijpHODNAn95gpen8Cop7qfGD51/eDlstvYt0c= From: Tomi Valkeinen Date: Fri, 27 Mar 2026 12:21:56 +0200 Subject: [PATCH v2 08/12] drm/bridge: tc358762: Support VTG Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260327-tc358762-fixes-v2-8-3589d3c45f4a@ideasonboard.com> References: <20260327-tc358762-fixes-v2-0-3589d3c45f4a@ideasonboard.com> In-Reply-To: <20260327-tc358762-fixes-v2-0-3589d3c45f4a@ideasonboard.com> To: Marek Vasut , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dave Stevenson , Tomi Valkeinen X-Mailer: b4 0.15-dev-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=3412; i=tomi.valkeinen@ideasonboard.com; h=from:subject:message-id; bh=qDgOvHrPx5VBCjCyaz4snC9nowUJ1uQTs9EWYBT2EmM=; b=owEBbQKS/ZANAwAIAfo9qoy8lh71AcsmYgBpxlpcNsqDgH8y2GjIikbc77QNJxyP27/8KWXnl +1LSGwqzbWJAjMEAAEIAB0WIQTEOAw+ll79gQef86f6PaqMvJYe9QUCacZaXAAKCRD6PaqMvJYe 9RJiEACRz+dMqwftX5IzdnlGnGY7983yUC5ZijLLOpdkd7Gs2DIjX7LUBCNIivalAdWAbdluLTn GVW6zh10NilujK2MKeZ+cM1qLS9bgqbsmzqTHV1nW17UKRflmQOmDI4Wjs7WEoXT6m9Tj91EcKK bTM9/GyXW+qzkipeTRq4dvDdedeRsIgA6XX3peFxqadzJhSlaDbxFCCLNSZrEGWT62CYJlMIxDc Ilmsl1tDYXqAwqHiNCnNZOOKVMhhnE9g4vuZXx4n8lsxMyYcOwAqrEq/r2ljZlMCIH/FCb1/5nm 0bckoPzDUEWUWoUc4SIUuHIu476EuToWgkXwm9LLR7vi7gIzvbt7PN1NQbegsIzJlbItZXERgKy Rd0Eh3d3hdwDdh7uS4b6YQzEePiPWhhBOComNFBhSODqz1z/jgyjORPNaJcwGuVQnTCnCQJjRP4 h/JJtu4fR0WGO+0VjIjDBmcMEREt/k66ehvLIUdluZ+2qY8J1knU31odi21XRtimWvhFdwlgxNF obKhAAjnJmJRs+/uG8yV7EOPi66rD5+LKouwEJWPM6DFFxUxMVNXxYyfnHl+kH2t6XV/sBzgpmx Rlcx0im/lUoWEhmhTB31Af7CmzvUOu2igeIEvjH27fBJuXQSdIOJKQyyV2yJyVkfYKrZg7HEkG5 OObSqkdEICXzfNA== X-Developer-Key: i=tomi.valkeinen@ideasonboard.com; a=openpgp; fpr=C4380C3E965EFD81079FF3A7FA3DAA8CBC961EF5 TC358762 can generate the DPI output's timings in two ways, either Video Timings Generator (VTG) on or off: - VTG off: Duplicate the timings coming from the DSI. This requires DSI pulse mode. - VTG on: Sync frame on DSI VSync Start, but the exact output timings are defined in TC358762 registers. This can be used with DSI event/burst mode. We are currently using VTG off in the driver. I observe that the hsync signal, on my HW setup, is not 100% stable with VTG off, and it seems to lengthen by a single clock every now and then. However, it then stabilizes later. To me the DSI input looks solid, but that is more challenging to measure exactly. So I have not found the root cause for this. Turning VTG on removes that instability. As I dont' see any downsides with enabling VTG (and it would allow extending the driver to use event/burst mode in the future), let's always enable the VTG. Signed-off-by: Tomi Valkeinen --- drivers/gpu/drm/bridge/tc358762.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/drivers/gpu/drm/bridge/tc358762.c b/drivers/gpu/drm/bridge/tc3= 58762.c index 9fb921b3fa0d..d3bcdf8af804 100644 --- a/drivers/gpu/drm/bridge/tc358762.c +++ b/drivers/gpu/drm/bridge/tc358762.c @@ -18,6 +18,7 @@ #include =20 #include