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 97246CE8D6B for ; Mon, 17 Nov 2025 03:57:29 +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:Content-Transfer-Encoding: Subject:Message-ID:MIME-Version:To:Cc:Date:References:Content-Type: In-Reply-To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BT04am3Kehc9aOs97jW5wTodqgxSkKf04K5hJUaJPzg=; b=dMPVbGsBlAFNqJ0ota3fr86X6S NNCIh5Yu4BpnhgpnKuJNekw8k4ApvdcrHDBIZh0XrXacnUwJFSanon81B8G4e/m8vkgYO7s7/ynwi YU2ede7FaXPf1vNxpRQYyOf/pLmsZex5+teFFytbrylNJOZeFhWGZmUClSCns48GMPbQIGkL7uRSI e3Oc2zGvNGTlYonazylVGMpmvgVoTpqf/i4UCT7ccrVyt0yBXk/7Hff/1CO/ObJxBuUO6PmxhqSiw rw1i0znRYb6R0VlfryZfNb+Je0y/WeZ++l0kEs93BWXoiWRGVYIUudx5ifVp7/zVtoTeBV+hN+qu4 lPYQsR6w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vKqMj-0000000FOf3-1uBx; Mon, 17 Nov 2025 03:57:21 +0000 Received: from mail1.manjaro.org ([2a01:4f8:c010:b6e8::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vKqMg-0000000FOed-2ToO; Mon, 17 Nov 2025 03:57:20 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPA id 8855841196; Mon, 17 Nov 2025 04:57:11 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=manjaro.org; s=dkim; t=1763351834; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=BT04am3Kehc9aOs97jW5wTodqgxSkKf04K5hJUaJPzg=; b=ReNdiVpeKrbgcSVmskmDotomCmwdsUx3+lrrU0N+K8oOwEV3dkiVyZQcohUTzaGNKRKgtk hYQeg1FoGF3ALHk6FnHSjPCylwzuNmoOROB/sIR2JgkwXRLPXXJyUkt5FtZYGs+l++rLVv j27F0p/AQ+LZm5JvqnMmp5we99oF8L1vBwyYj3OerttrRhPqqNq28yIBRY7ClbHIy/yamE lR4bThz0szV2dhvXjmty4JyC/IAItlWzSNa3kC+Md03xB4Z+TEZSUL5NgqEoLHZzudlAPP 3yKvBIVIkDFCwAh8mhmlshQ5zUoBjFMjc8AkyMspHhP18woVqWhU4LspaHFCRQ== From: "Dragan Simic" In-Reply-To: <8f3cc1c1-7bf7-4610-b7ce-79ebd6f05a6e@rock-chips.com> Content-Type: text/plain; charset="utf-8" References: <8f3cc1c1-7bf7-4610-b7ce-79ebd6f05a6e@rock-chips.com> Date: Mon, 17 Nov 2025 04:57:11 +0100 Cc: "Geraldo Nascimento" , "Lorenzo Pieralisi" , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , "Manivannan Sadhasivam" , "Rob Herring" , "Bjorn Helgaas" , "Heiko Stuebner" , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, "Krzysztof Kozlowski" , "Conor Dooley" , "Johan Jonker" , linux-rockchip@lists.infradead.org To: "Shawn Lin" MIME-Version: 1.0 Message-ID: <257951b7-c22e-9707-6aba-3dc5794306bb@manjaro.org> Subject: =?utf-8?q?Re=3A?= [PATCH 0/3] =?utf-8?q?PCI=3A?==?utf-8?q?_rockchip=3A?= =?utf-8?q?_5=2E0?= GT/s speed may be dangerous User-Agent: SOGoMail 5.12.3 Content-Transfer-Encoding: quoted-printable X-Last-TLS-Session-Version: None X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251116_195718_884200_FAFA1352 X-CRM114-Status: GOOD ( 12.24 ) 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 Hello Shawn and Geraldo, On Monday, November 17, 2025 04:42 CET, Shawn Lin wrote: > =E5=9C=A8 2025/11/15 =E6=98=9F=E6=9C=9F=E5=85=AD 17:10, Geraldo Nasci= mento =E5=86=99=E9=81=93: > > In recent interactions with Shawn Lin from Rockchip it came to my > > attention there's an unknown errata regarding 5.0 GT/s operational > > speed of their PCIe core. According to Shawn there's grave danger > > even if the odds are low. To contain any damage, let's cover the > > remaining corner-cases where the default would lead to 5.0 GT/s > > operation as well as add a comment to Root Complex driver core, > > documenting this danger. >=20 > I'm not sure just adding a warn would be a good choice. Could we tota= lly > force to use gen1 and add a warn if trying to use Gen2. I think that forcing 2.5 GT/s with an appropriate warning message is a good idea. That would be like some quirk that gets applied automatically, to prevent data corruption, while warning people who attempt to "overclock" the PCIe interface. > Meanwhile amend the commit message to add a reference > of RK3399 official datesheet[1] which says PCIe on RK3399 should only > support 2.5GT/s? >=20 > [1]https://opensource.rock-chips.com/images/d/d7/Rockchip=5FRK3399=5F= Datasheet=5FV2.1-20200323.pdf Also, rewording the patch summary as follows below may be good, because that would provide more details: PCI: rockchip: Warn about Gen2 5.0 GT/s on RK3399 being unsafe Or, if we'll go with the automatic downgrading, like this: PCI: rockchip: Limit RK3399 to Gen1 2.5 GT/s to prevent breakage