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 586F1C369B5 for ; Mon, 14 Apr 2025 10:13:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=M5TSWw6YSYb3Im+tA0wySsNFKR01ijlY33rOknNYTJs=; b=SneV3fPy6OmQ3n 2E7ADQzFkZ1rZ0r44VNufF/Ad6UTl8xsE2eXVVtDHZtm7CfSqYlB2Y97V+3feihXSz1PQWyocgzXJ CzjHaV33njiiDv0WyKEQMrH4vGQ7jW1OB6HC5r74dxMlQIKzFjzhr4rdhT2hvdxkUJo5QE0Ctl4Al Eq/wCtWkb9XZT4mkWd2tHOODlfMCVcN5aw6lTRx8gpvrikII3YYjwqBK1/e1XuQ8cJO8GnkbNovoS UljwJsnOEoXSMKmjeiK4LkoTSb+YHbjPdT66smW6ItfoRVebOA7BoJgAJBo2kty2W820PvwoMWklg 0FT0sVYbBsicUgLPXPRw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u4Gos-00000001S6Y-45E6; Mon, 14 Apr 2025 10:13:38 +0000 Received: from nyc.source.kernel.org ([147.75.193.91]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u4Ghi-00000001PQ7-3xUh for linux-rockchip@lists.infradead.org; Mon, 14 Apr 2025 10:06:16 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id B9DC2A49BF1; Mon, 14 Apr 2025 10:00:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49B25C4CEE2; Mon, 14 Apr 2025 10:06:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744625173; bh=i2lYtsZGAS9XdlrMapzUnk0eGNmZJKYqS1yBto1gtek=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dnb1SXSdLlWm+dU/DMNl+RyKzZc5LSYXzbUMlbKHC/QRtbHQXOFlpDtVLJefjzVgS Y/OfrRTqvgGJmx5mZpAph8cMY23YCapEH30D6U6PatxkEQTfgZzvoNilS9NO5EoxX0 asAzr60r9aM1TNTcEiRtn+n0ztMCQ5sUHF2R1tP35VZzpytZ39d9vFjTGHz3LvQCQd BAhqL+X4qdb+0dHY6UuSmwemOfxk5IM5ec4+VSMnqK6N+Pti4XcKV+JuDWF+TXIff+ 7L2lu80MJLKB2BYozNxjS1fPxG7ZpliI8Pp7q8YIJsLCQU4yyn8p7mF37ptpI93FDT tLFZCZHWcv+SQ== Date: Mon, 14 Apr 2025 12:06:09 +0200 From: Niklas Cassel To: Manivannan Sadhasivam Cc: Shawn Lin , Bjorn Helgaas , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , linux-pci@vger.kernel.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH] PCI: dw-rockchip: Remove PCIE_L0S_ENTRY check from rockchip_pcie_link_up() Message-ID: References: <1744180833-68472-1-git-send-email-shawn.lin@rock-chips.com> <38e69551-cc40-11a9-191f-de9a193c5e51@rock-chips.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250414_030615_051165_7857383B X-CRM114-Status: GOOD ( 14.59 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org Hello Mani, On Sun, Apr 13, 2025 at 07:54:28PM +0530, Manivannan Sadhasivam wrote: > On Wed, Apr 09, 2025 at 11:19:03AM +0200, Niklas Cassel wrote: > > > > It seems like we should really add a warning and a comment in > > dw_pcie_link_up(), so that others don't get hit by this hard to debug issue! > > > > Right. But I'm also wondering if we should use the 'Data Link Layer Link Active' > bit in PCI Express Capability for checking link up. Qcom driver has been using > it from the start and there are no reported issues. We could add this as the > first fallback if the link_up callback is not provided. Sounds like a good idea, but from looking at: 7.5.3.6 Link Capabilities Register (Offset 0Ch) " Data Link Layer Link Active Reporting Capable - For a Downstream Port, this bit must be hardwired to 1b if the component supports the optional capability of reporting the DL_Active state of the Data Link Control and Management State Machine. For a hot-plug capable Downstream Port (as indicated by the Hot-Plug Capable bit of the Slot Capabilities Register) or a Downstream Port that supports Link speeds greater than 5.0 GT/s, this bit must be hardwired to 1b. For Upstream Ports and components that do not support this optional capability, this bit must be hardwired to 0b. " It sounds like the the 'Data Link Layer Link Active' bit is optional, or at least optional for Gen1 and Gen2. Kind regards, Niklas _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip