From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-201.mailbox.org (mout-p-201.mailbox.org [80.241.56.171]) (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 8C56B3A0B2C for ; Fri, 27 Feb 2026 10:41:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772188900; cv=none; b=mFYCE8hI7rDmkKVaiEA9uMkzcc6yGfa59e3dKQwO0AGT6hBFxYraYR5yWkSEL1HIcncgNDvY6KrgY1Y6zNnacBJsXLQTfhP+tm4RmzuMUdZndObWZIg6KWr0/DhCJHBHhkikX4y6JVv/Maw4QYeigPzEc5s+utcI+in5jjlU/Nc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772188900; c=relaxed/simple; bh=G0h5lLcwv6kaANEI9Gc3rEGHdwQPx+dd1VsItJ6RXDU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ql8S8OnhFd3viAanJbboOhPvOTAi7jH5BXdVUzgGqLD5mvlUrcHNnbCvB6EMEoPNNuInVenI6GZArQ9QK5LSxew0Uouqjhf82UJl9GRbKTLJhGdvEQfYqQ6x2t8T09xJms+ykrDhotuMiZOmwWvylUkXeBjCpyPzAodTbKQW2Zw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org; spf=pass smtp.mailfrom=mailbox.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b=lRgj3bQk; arc=none smtp.client-ip=80.241.56.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mailbox.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b="lRgj3bQk" Received: from smtp1.mailbox.org (smtp1.mailbox.org [IPv6:2001:67c:2050:b231:465::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 4fMlHg3YJvz9scQ; Fri, 27 Feb 2026 11:41:35 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1772188895; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Vx85JChNWo+JtUQhDDnJNFqSm7CFk9xMUNm2UDb9UcE=; b=lRgj3bQkF0YKnEl+03B6syorqyklvdpC2A0HJNOzb5joZzG2+v0u4gUMcseQUJI2nBKU3K kNyyRfP4Yr2rjOaL54kQIDIXd9HZoTNIVsx0QatAUeKFEFPTpP9StO4HXwE86oECeCRDg5 +ugSRex4vWNToPVBJYcxm8x7tdPbES0gZxJHHCnwgApeABlwbudFR3WPArt9nTUbV6xIUr vT2KBSWaXo0afZ9QLo72gcftP8hHGVVw95Mt87zjKrWDnqlAXRB0dXAv5AZLMq/+MFHKeM BWLjwVPWzIPxeOir1s8tjf7VrS/yRhs4cxveLdKE+aqJW86PqSCIm8NyvR+kbg== Message-ID: <71224e5f-d982-45f9-be91-b61b78f38853@mailbox.org> Date: Fri, 27 Feb 2026 11:41:29 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH 3/3] drm/bridge: ti-sn65dsi83: add test pattern generation support To: Luca Ceresoli , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Frieder Schrempf , Marek Vasut , Linus Walleij Cc: Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org 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> Content-Language: en-US From: Marek Vasut In-Reply-To: <20260226-ti-sn65dsi83-dual-lvds-fixes-and-test-pattern-v1-3-2e15f5a9a6a0@bootlin.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-MBO-RS-ID: e288f7890a15b977c7e X-MBO-RS-META: 1t3xkckrmdiizbrogzmcuifpfw38xchc 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. > > 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 stated 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. > > [0] https://www.ti.com/tool/DSI-TUNER > > Signed-off-by: Luca Ceresoli > --- > drivers/gpu/drm/bridge/ti-sn65dsi83.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/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 ?