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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DB411CD5BD0 for ; Sat, 30 May 2026 18:54:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4E4E311297F; Sat, 30 May 2026 18:54:33 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=geanix.com header.i=@geanix.com header.b="F+2f5duo"; dkim-atps=neutral Received: from mail-4327.protonmail.ch (mail-4327.protonmail.ch [185.70.43.27]) by gabe.freedesktop.org (Postfix) with ESMTPS id E50B911297F for ; Sat, 30 May 2026 18:54:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=geanix.com; s=protonmail3; t=1780167110; x=1780426310; bh=6hqDjImuAem/6OD61cXZG6OTmI0pwB62MXq+JBsU1ro=; h=Date:To:From:Cc:Subject:Message-ID:Feedback-ID:From:To:Cc:Date: Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector; b=F+2f5duosDoNeeas6k96BIJQWCi40bwxVBoqIt02focXKYWocMzPVIyh7+ejcgi+8 MVBlI2w7lKe2Ez6ePyHcqv2ZDMOl+8yIwI1xmh7lyVNkLfDTJDqHlwfbbKDbrTVXXm INOHt+hbL7n3xD7tLa/1EJVG3M40uZIXrWWwpaulQofj+Lldy2H3dvOyjB9K3+sIol 6OTtluybHinTDEgw6a8F7TURF9B6Rti2rxFGKgP8jEEH+MDLk4qelyP3xKJRCVr+dg 8WINYj7kKvSBxo7cd7ADgXzCQPYUx8R7KlngJ3pe5bjqKuXNldHpCklMCViLr8ECtM I3I28Sz/5b5KQ== Date: Sat, 30 May 2026 18:51:42 +0000 To: Sudarshan Shetty , luca.ceresoli@bootlin.com From: Sean Nyekjaer Cc: andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org, Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se, jernej.skrabec@gmail.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, alexander.stein@ew.tq-group.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 2/2] drm: bridge: ti-sn65dsi83: Disable video burst mode for LVDS stability Message-ID: Feedback-ID: 134068486:user:proton X-Pm-Message-ID: aa8b75addb1c0b0e117d1a5c77bbeb83e9192027 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Luca, On Wed, May 27, 2026 at 02:27:36PM +0100, Sudarshan Shetty wrote: > The current DSI configuration enables MIPI_DSI_MODE_VIDEO_BURST. > while burst mode is supported by the hardware, its use > depends on continuous clock behavior from the DSI host. In practice, > burst mode may introduce instability depending on the host controller > implementation, as the DSI link may transition to low-power state > between bursts. >=20 > Testing showed improved display stability when using non-burst mode on > affected panels. >=20 > Remove MIPI_DSI_MODE_VIDEO_BURST and use non-burst video mode. >=20 We briefly talked about this at Embedded Recipes I promised to sent a link: https://lore.kernel.org/all/E35054BA-FBE5-4CEE-905C-1F5D20140590@geanix.com= / When burst mode is enabled, the LVDS clock gets way to high for my panel. I don't know if it's the DSI controller in the STM32MP1 or something not supported on the TI side. We have been running with this fix for 2 years :) > Tested-by: Luca Ceresoli > Tested-by: Alexander Stein > Signed-off-by: Sudarshan Shetty Tested-by: Sean Nyekjaer > --- > drivers/gpu/drm/bridge/ti-sn65dsi83.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) >=20 > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/brid= ge/ti-sn65dsi83.c > index c03ff1ea9df8..6b5a6019c30d 100644 > --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c > @@ -976,8 +976,8 @@ static int sn65dsi83_host_attach(struct sn65dsi83 *ct= x) > =20 > =09dsi->lanes =3D dsi_lanes; > =09dsi->format =3D MIPI_DSI_FMT_RGB888; > -=09dsi->mode_flags =3D MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST | > -=09=09=09 MIPI_DSI_MODE_VIDEO_NO_HSA | MIPI_DSI_MODE_NO_EOT_PACKET; > +=09dsi->mode_flags =3D MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_NO_HSA = | > +=09=09=09 MIPI_DSI_MODE_NO_EOT_PACKET; > =20 > =09ret =3D devm_mipi_dsi_attach(dev, dsi); > =09if (ret < 0) { > --=20 > 2.34.1 >=20