From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4897D240611 for ; Fri, 27 Feb 2026 10:57:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772189864; cv=none; b=EGOfe1a91nPBdlHSL5YCWpPCuTOuC5bPTksGWoYgTVs99kCHn6Bhq1WE3bUZS7Rbdm8S3UBxFF6ijT2QljpaLtF6C0BLV+/6c1Y9SWpWm1YAtNEE/9GLqTo6ygXJy89YVj665EfgQGwS9x8T3SYYlTxcBWy+jReVjsPCv0nWd+k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772189864; c=relaxed/simple; bh=EV++6fc7wgpSpcgWlcOMt/xe137qRBgNctkEkpXLWgg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=aEv6gm+k3uAeXbDP3eLSuiUx7zcMvBFKgxunKUNKaWpwBQVrH2mUWlpaGEW9VEY2Rlc6eQgpcY4VElXGFZmZM+Wk94LfTM23NkHZB/42fVrHHQll8jolayzXsSxcCP5aK8QFl/W8fo4xchu6edTrjtjvQ3KYaHqKkxo3rlxkdN8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uKoU2ttm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uKoU2ttm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37C45C116C6; Fri, 27 Feb 2026 10:57:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772189863; bh=EV++6fc7wgpSpcgWlcOMt/xe137qRBgNctkEkpXLWgg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uKoU2ttmFrLP8NXYua797uuFYuyvTHBm7A3f1waYp51zq550diTXVRbTPT0ytknvR Z1z8jXzG22BA9F5LoHq3fzwR+/LcNbTGjnD0dfTmVkvA/r6YEfbzjxPI3PYzmhiWsC REk8cRAu+CuYzk9fkocrzJfBt+u8RUxQ+/tK9yTxWKJz4q3xoOBA2FwdK4Qkhmjw8w oBMMtdNLDIw9r/h1bNZbknWbDdJeJyrd8J7/mW14Rhjj6UBrL5ZJ4LASAJMDHeffCr 1D5D9g99OyxsqbwithM1CPBnz1N5fHrLBh5VyK2cDFwv90Ay7sqM2orzSiyFsWDnb6 +bhf5t0KKA4lg== Date: Fri, 27 Feb 2026 11:57:40 +0100 From: Maxime Ripard To: Marek Vasut Cc: Luca Ceresoli , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter , Frieder Schrempf , Marek Vasut , Linus Walleij , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] drm/bridge: ti-sn65dsi83: add test pattern generation support Message-ID: <20260227-loud-silky-macaw-8d4d3b@houat> References: <20260226-ti-sn65dsi83-dual-lvds-fixes-and-test-pattern-v1-0-2e15f5a9a6a0@bootlin.com> <20260226-ti-sn65dsi83-dual-lvds-fixes-and-test-pattern-v1-3-2e15f5a9a6a0@bootlin.com> <71224e5f-d982-45f9-be91-b61b78f38853@mailbox.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha384; protocol="application/pgp-signature"; boundary="biqdddwbes3n3dob" Content-Disposition: inline In-Reply-To: <71224e5f-d982-45f9-be91-b61b78f38853@mailbox.org> --biqdddwbes3n3dob Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH 3/3] drm/bridge: ti-sn65dsi83: add test pattern generation support MIME-Version: 1.0 On Fri, Feb 27, 2026 at 11:41:29AM +0100, Marek Vasut wrote: > On 2/26/26 5:16 PM, Luca Ceresoli wrote: > > Generation of a test pattern output is a useful tool for panel bringup = and > > debugging, and very simple to support with this chip. > >=20 > > The value of REG_VID_CHA_ACTIVE_LINE_LENGTH_LOW needs to be divided by = two > > for the test pattern to work in dual LVDS mode. While not clearly state= d in > > the datasheet, this is needed according to the DSI Tuner [0] output. And > > some dual-LVDS panels refuse to show any picture without this division = by > > two. > >=20 > > [0] https://www.ti.com/tool/DSI-TUNER > >=20 > > Signed-off-by: Luca Ceresoli > > --- > > drivers/gpu/drm/bridge/ti-sn65dsi83.c | 13 +++++++++++-- > > 1 file changed, 11 insertions(+), 2 deletions(-) > >=20 > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/br= idge/ti-sn65dsi83.c > > index 17a885244e1e..ddc8b5e1dd15 100644 > > --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c > > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c > > @@ -114,6 +114,7 @@ > > #define REG_VID_CHA_HORIZONTAL_FRONT_PORCH 0x38 > > #define REG_VID_CHA_VERTICAL_FRONT_PORCH 0x3a > > #define REG_VID_CHA_TEST_PATTERN 0x3c > > +#define REG_VID_CHA_TEST_PATTERN_EN BIT(4) > > /* IRQ registers */ > > #define REG_IRQ_GLOBAL 0xe0 > > #define REG_IRQ_GLOBAL_IRQ_EN BIT(0) > > @@ -134,6 +135,9 @@ > > #define REG_IRQ_STAT_CHA_SOT_BIT_ERR BIT(2) > > #define REG_IRQ_STAT_CHA_PLL_UNLOCK BIT(0) > > +static bool sn65dsi83_test_pattern; > > +module_param_named(test_pattern, sn65dsi83_test_pattern, bool, 0644); > > Can this be enabled/disabled at runtime via sysfs attribute instead ? Then you would have to deal with concurrency with the atomic state updates, and it would really be better implemented as a connector property. In other words, it's probably enough for now :) Maxime --biqdddwbes3n3dob Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJUEABMJAB0WIQTkHFbLp4ejekA/qfgnX84Zoj2+dgUCaaF4pAAKCRAnX84Zoj2+ dmfGAYCXrIMmmlOgJt3MTEOT4TgCw+0VLkqRfKu/QjAEEEHfpUQtW8l3Qwj/APbO b4lUOGMBgMZstfRKFeohlKrLQdrYO0mNeA3W79oQEPgEJgK3dTYlFxD3JT3llzax SoEiSaFyOw== =5fXu -----END PGP SIGNATURE----- --biqdddwbes3n3dob--