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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 31157D65C4F for ; Wed, 17 Dec 2025 14:20:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:References:Cc: Subject:From:To:Message-Id:Date:Content-Type:Content-Transfer-Encoding: Mime-Version:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=FXeSnaeUCeq2poCC8SB7HwoeEyqC5tY0nRKawuzYQpY=; b=txCMAFWX5RY8iNlzqXsqqBPla2 5faiCOZ/ZUxD1v2j417Xgs7N5v3SN2r/D5yx7/J/SoPRiYznr2RSYxm4mI9rlc4aEm7GSFRPlOn/I 92jFHg7ZzNB0neJ30PzmIGCBTX/cH6Kpd35GfOevh6yCFvnX1swbJHOhhGQstXCt9fT3VJSZhn9Vx PcOywDWCMb4USuP41A612K0U0n40dv8vWc0lo+kE362pEDggU+lZOFBcu7f0nilLSOoezFpAQVmJg /Xyzp9Lro3NUxG3HnoDyZ4MShzI8EKBEpWhh+32myWyoTHi389LumvcRKmNovnMIlWQgJMaP6veYc 1JgweC0w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vVsOF-00000006urr-3HWt; Wed, 17 Dec 2025 14:20:31 +0000 Received: from smtpout-03.galae.net ([185.246.85.4]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vVsOC-00000006uqd-2pxj for linux-arm-kernel@lists.infradead.org; Wed, 17 Dec 2025 14:20:31 +0000 Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id 1AB454E41C63; Wed, 17 Dec 2025 14:20:25 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id D2B406072F; Wed, 17 Dec 2025 14:20:24 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id C5F1C102F0AD5; Wed, 17 Dec 2025 15:20:10 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1765981219; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=FXeSnaeUCeq2poCC8SB7HwoeEyqC5tY0nRKawuzYQpY=; b=LHcy7tbcWgKNnbGmUxOlMOBySmxpFEfq3HpPYCboxqOS0InHSE2jsyLPoDc6g1K2IZE/7t 3buuqUiZoTVvR0KidqwpqnHZzuKCUrptEpiBRoyQ+XN66Ig72pyOXXTojG9kVBcfJkjeps An6pX7EtnKRkGqT25rAc1S1a38lAMmftuJ6bcaNx/7W/7w4s3gmhv6/Hmo2jd27iegZQtk lwjk63yzkf+h3o1fjamDFT12Z/8OSL8U62AuB06sLvCQTTeox8gqrmmjCBjcoqZSdvcbtH 4OAyX3SjocA/4RKzdC1VUi35zIKIQVzSlYEL8nN7+dYicXCQbgjQOJo3UvTMFA== Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 17 Dec 2025 15:20:09 +0100 Message-Id: To: "Kory Maincent (TI.com)" , "Jyri Sarha" , "Tomi Valkeinen" , "Maarten Lankhorst" , "Maxime Ripard" , "Thomas Zimmermann" , "David Airlie" , "Simona Vetter" , "Rob Herring" , "Krzysztof Kozlowski" , "Conor Dooley" , "Russell King" , "Bartosz Golaszewski" , "Tony Lindgren" , "Andrzej Hajda" , "Neil Armstrong" , "Robert Foss" , "Laurent Pinchart" , "Jonas Karlman" , "Jernej Skrabec" From: "Luca Ceresoli" Subject: Re: [PATCH v2 03/20] drm/tilcdc: Remove simulate_vesa_sync flag Cc: "Markus Schneider-Pargmann" , "Bajjuri Praneeth" , "Louis Chauvet" , "Thomas Petazzoni" , "Miguel Gazquez" , , , , , X-Mailer: aerc 0.20.1 References: <20251211-feature_tilcdc-v2-0-f48bac3cd33e@bootlin.com> <20251211-feature_tilcdc-v2-3-f48bac3cd33e@bootlin.com> In-Reply-To: <20251211-feature_tilcdc-v2-3-f48bac3cd33e@bootlin.com> X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251217_062028_843926_61481031 X-CRM114-Status: GOOD ( 13.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi K=C3=B6ry, On Thu Dec 11, 2025 at 5:38 PM CET, Kory Maincent (TI.com) wrote: > The tilcdc hardware does not generate VESA-compliant sync signals. It > aligns the vertical sync (VS) on the second edge of the horizontal sync > (HS) instead of the first edge. To compensate for this hardware > behavior, the driver applies a timing adjustment in mode_fixup(). > > Previously, this adjustment was conditional based on the simulate_vesa_sy= nc > flag, which was only set when using external encoders. This appears > problematic because: > > 1. The timing adjustment seems needed for the hardware behavior regardles= s > of whether an external encoder is used > 2. The external encoder infrastructure is driver-specific and being > removed due to design issues > 3. Boards using tilcdc without bridges (e.g., am335x-evm, am335x-evmsk) > may not be getting the necessary timing adjustments > > Remove the simulate_vesa_sync flag and apply the VESA sync timing > adjustment unconditionally, ensuring consistent behavior across all > configurations. While it's unclear if the previous conditional behavior > was causing actual issues, the unconditional adjustment better reflects > the hardware's characteristics. > > Signed-off-by: Kory Maincent (TI.com) Code looks good. Based on your testing, which covered both boards currently setting simulate_vesa_sync and boards not setting it: Reviewed-by: Luca Ceresoli Still it would be good to have this series, and especially this patch, tested by someone having access to other TI boards. -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com