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 B93733451C6; Tue, 11 Nov 2025 14:00:07 +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=1762869607; cv=none; b=aP8kodhbJk3p/J9PTDZR7RO+ull/SlYDVXm7yvJuBv/Bjsy8z1tLNlVkIKCHH/cepfX5f3lNRzFrN2y/JO7CkbxC7EfggL/hpVv5fFPP5/U88cUYvCzrUN86WWdDH7qdXcUzIBEUgjE3L2xUIwjvtzqtYbuyCa/shid2MEbVAQU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762869607; c=relaxed/simple; bh=D1S3OL4p0+J4mWcZ2dm1aw9L5R0M+rOLhxjglXPSaEc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jGaLNvVdQGE4K200Txnaaq+EGRGvjGLHGCVe0u4n84btaWTweJrnkjdQDP0uyLCVqHTzIGr3GfQ2SLKV1rA6XZQRDAmkRMPtM+qEm1IYu3aKiDcsVHQYKc+C4orfup06g29JQH8vKl5WAEDlfhYm7pJKbSyPRB3FPAyvbp/jW4Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BK6yS3ik; 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="BK6yS3ik" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2B6CC113D0; Tue, 11 Nov 2025 14:00:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762869607; bh=D1S3OL4p0+J4mWcZ2dm1aw9L5R0M+rOLhxjglXPSaEc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BK6yS3ikNQGdeSm87kJZrIJJ2XY6POhOH7MZmL27V0Z5S3dw3nYncaxgaHcY1Lu+F JfFL1HyiOjKsoFotilBRDoOwnVtfEN+Am17dFZfdhl0iJzjCla5OqcEAQDJEoJm/UW zQl/cTwTmOjKHw9ttl9MFYwgAmc2524Srxq/IfABJDKxLrba4bc4JT3yXrBsZMKi5H Da2hh7/+bYFZH+VSJUbPQjShpd8y+P5ZonC8DCmnRcV2ZQTaP9oh5X/y2e05XA9pX1 V2vT6CqyqJnODCdbHc0Dsnc313OsQ0rZJdxY80KZzyZZThukX8LeGbI/ySB71OPEQO kUp8PlC3G+pJQ== Date: Tue, 11 Nov 2025 15:00:01 +0100 From: Niklas Cassel To: Shawn Lin Cc: FUKAUMI Naoki , Damien Le Moal , Anand Moon , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, Dragan Simic , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , Bjorn Helgaas , Heiko Stuebner , Manivannan Sadhasivam Subject: Re: [RESEND] Re: [PATCH] PCI: dw-rockchip: Skip waiting for link up Message-ID: References: <780a4209-f89f-43a9-9364-331d3b77e61e@rock-chips.com> <4487DA40249CC821+19232169-a096-4737-bc6a-5cec9592d65f@radxa.com> <363d6b4d-c999-43d4-866e-880ef7d0dec3@rock-chips.com> <0C31787C387488ED+fd39bfe6-0844-4a87-bf48-675dd6d6a2df@radxa.com> <2n3wamm3txxc6xbmvf3nnrvaqpgsck3w4a6omxnhex3mqeujib@2tb4svn5d3z6> <05bd0efe-9a84-40e9-af07-51c0b0d865bf@rock-chips.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <05bd0efe-9a84-40e9-af07-51c0b0d865bf@rock-chips.com> On Tue, Nov 11, 2025 at 11:17:23AM +0800, Shawn Lin wrote: > > > > It works stably on the ROCK 5A. The link speed is 2Gb/s. > > > > The ROCK 5C is unstable. It initially worked with a link speed of 4Gb/s, > > but eventually started showing kernel oops. The dts files for the 5A and > > 5C are compatible and interchangeable, but even using the 5A's dts on > > the 5C, the operation remains unstable. > > The link speed on ROCK 5A is 2Gb/s also means it's downgraded now. Did > ROCK 5A work under the link speed of 4Gb/s before? > > In case it's signal integrity relevant, you could enable PCIE_DW_DEBUGFS > and refer to Documentation/ABI/testing/debugfs-dwc-pcie to collect > RASDES info from there. Just a quick note: I've noticed that you cannot blindly look at the link speed in dmesg. E.g. on my ROCK 5B boards, I can occasionally see something like: [ 1.417181] pci 0000:01:00.0: 4.000 Gb/s available PCIe bandwidth, limited by 5.0 GT/s PCIe x1 link However, if I check the actual link speed with lspci after boot: # lspci -vvv -s 0000:01:00.0 | grep LnkSta: LnkSta: Speed 8GT/s, Width x4 I can see that the link is actually using the correct speed + number of lanes. Kind regards, Niklas