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 61FFEC43458 for ; Wed, 8 Jul 2026 10:43:24 +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: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=98rENIB3mGoVN8IzGK5+Rv/mhcjDzkejvD/k8HXEbKY=; b=uY6lUAuaNclwUheOt3Viw0hWhf 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References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding:cc:content-transfer-encoding: content-type:date:from:message-id:mime-version:reply-to:subject: to; b=HmvSYbVGsxRsgzkFyCHKY11mw7awZ6ax2mPPLLHmDK2UyiR5KmdcM3JSgBMWF4nM y5gb0mCvvdiV37QH0GaXOXpVAtLDRTNnnv+UXZUooPdGecUIRLfc18joPYewUkHWg abp/x3Lf77/vNa6J4vMM4UfCi2hM812UisyYKpJKmokJjBXVXx/lqigH3qaAy04Na b293HYtXB4I/ldabkmVV5+YaMI4416WXFG7sCzjcAN0kx9ZMSvVFfbLQYWTTmiUWu ZMvrgwiSx91wjLGa3TphOELQqukIuAu1u2A4iApYJiONKqV7NBkybOrW6o7hjc7xh 52mf5r65GVDe1a+wIg== X-UI-Sender-Class: 814a7b36-bfc1-4dae-8640-3722d8ec6cd6 Received: from client.hidden.invalid by smtp.web.de (mrweb106 [213.165.67.124]) with ESMTPSA (Nemesis) id 1MBB80-1wmKLh42DW-00Bg5x; Wed, 08 Jul 2026 12:43:12 +0200 Message-ID: <04ff27d2-2b9e-4ca5-918d-8c4211685eae@web.de> Date: Wed, 8 Jul 2026 12:43:08 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1] PCI: imx6: Fix i.MX6Q/DL boot hang by separating PHY power and reference clock control To: "Hongxing Zhu (OSS)" , Frank Li , "l.stach@pengutronix.de" , "lpieralisi@kernel.org" , "kwilczynski@kernel.org" , "mani@kernel.org" , "robh@kernel.org" , "bhelgaas@google.com" , "s.hauer@pengutronix.de" , "kernel@pengutronix.de" , "festevam@gmail.com" Cc: "linux-pci@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "imx@lists.linux.dev" , "linux-kernel@vger.kernel.org" , Hongxing Zhu References: <20260706030629.3264320-1-hongxing.zhu@oss.nxp.com> <4836b6f1-d40d-479d-acf7-a67769e0c8ac@web.de> <0c649fcb-f084-4cc2-bed4-cc335b40c599@web.de> Content-Language: en-US, de-DE From: Soeren Moch In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:O4IzZMH8IYa+aCtKatLsZYQxcvdLppHR6JLxIrgPN5Zh0ZxGm3K SikqpQSdkwWXLSwudfvLiNMKEj10lxoXc/18mb9ZezMuT8jkjYMC907hhs3ce8aczp2j5B4 wNZyES7EUFTn+QiCRxY5efypH7yTcG5kaxChIohk3EDxvkXhOFkv6ygKSB4R49tm5pn7Fev 2efztF8wMB81wFseQamIA== UI-OutboundReport: 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aoBE54Evy2QbTP8eb/u58ioRpD6RvH0aKol47ICTibKmFpQnG9deu2L1X5Cjho+ABfGy57xme 4YRBbVPL0mkgjDToWwZk1fJMpxIft/nWWNB6fjFGKurvGMKlgqTD1lAsQE9gujejSQyI1tIi+ sPxTBaDuQS7n2KmKFiGDr0yVnTSgS+ X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260708_034315_271310_B52189DE X-CRM114-Status: GOOD ( 17.74 ) 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 On 08.07.26 11:50, Hongxing Zhu (OSS) wrote: >> -----Original Message----- >> From: Soeren Moch >> Sent: Tuesday, July 7, 2026 7:04 PM >> To: Hongxing Zhu (OSS) ; Frank Li >> ; l.stach@pengutronix.de; lpieralisi@kernel.org; >> kwilczynski@kernel.org; mani@kernel.org; robh@kernel.org; >> bhelgaas@google.com; s.hauer@pengutronix.de; kernel@pengutronix.de; >> festevam@gmail.com >> Cc: linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org; >> imx@lists.linux.dev; linux-kernel@vger.kernel.org; Hongxing Zhu >> >> Subject: Re: [PATCH v1] PCI: imx6: Fix i.MX6Q/DL boot hang by separatin= g PHY >> power and reference clock control >> >> On 07.07.26 10:55, Soeren Moch wrote: >>> On 07.07.26 05:03, Hongxing Zhu (OSS) wrote: >>>>> -----Original Message----- >>>>> From: Soeren Moch >>>>> Sent: Monday, July 6, 2026 10:09 PM >>>>> To: Hongxing Zhu (OSS) ; Frank Li >>>>> ; l.stach@pengutronix.de; lpieralisi@kernel.org; >>>>> kwilczynski@kernel.org; mani@kernel.org; robh@kernel.org; >>>>> bhelgaas@google.com; s.hauer@pengutronix.de; kernel@pengutronix.de; >>>>> festevam@gmail.com >>>>> Cc: linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org; >>>>> imx@lists.linux.dev; linux-kernel@vger.kernel.org; Hongxing Zhu >>>>> >>>>> Subject: Re: [PATCH v1] PCI: imx6: Fix i.MX6Q/DL boot hang by >>>>> separating PHY power and reference clock control >>>>> >>>>> >>>>> >>>>> On 06.07.26 05:06, hongxing.zhu@oss.nxp.com wrote: >>>>>> From: Richard Zhu >>>>>> >>>>>> Commit 610fa91d9863 ("PCI: imx6: Assert PERST# before enabling >>>>>> regulators") introduced a boot hang on i.MX6Q/DL variants by >>>>>> changing the initialization sequence. >>>>>> >>>>>> The issue stems from coupling PHY power (TEST_PD) and reference >>>>>> clock >>>>>> (REF_CLK_EN) control in imx6q_pcie_enable_ref_clk(). When these are >>>>>> managed together, the timing between PHY power-up and reference >>>>>> clock enablement cannot be properly controlled, leading to >>>>>> initialization failures. >>>>>> >>>>>> Fix this by separating the two concerns: >>>>>> >>>>>> - Move PHY power control (TEST_PD) to imx6q_pcie_core_reset() where >>>>>> it >>>>>> =C2=A0=C2=A0=C2=A0 logically belongs with reset operations. This e= nsures PHY power >>>>>> state >>>>>> =C2=A0=C2=A0=C2=A0 is managed as part of the core reset sequence. >>>>>> >>>>>> - Update imx6qp_pcie_core_reset() to call imx6q_pcie_core_reset() >>>>>> for >>>>>> =C2=A0=C2=A0=C2=A0 shared PHY power management, avoiding code dupl= ication. >>>>>> >>>>>> - Make imx6q_pcie_enable_ref_clk() responsible only for reference >>>>>> clock >>>>>> =C2=A0=C2=A0=C2=A0 (REF_CLK_EN) control, simplifying its purpose. >>>>>> >>>>>> - Remove the 10us delay workaround from imx6q_pcie_enable_ref_clk() >>>>>> as >>>>>> =C2=A0=C2=A0=C2=A0 proper sequencing is now handled by the core_re= set functions. >>>>>> >>>>>> This refactoring ensures PHY power is controlled during reset >>>>>> operations, fixing the boot hang while improving code maintainabili= ty. >>>>>> >>>>>> Fixes: 610fa91d9863 ("PCI: imx6: Assert PERST# before enabling >>>>>> regulators") >>>>>> Signed-off-by: Richard Zhu >>>>> With this patch on top of v7.2-rc2 I see everything booting, lspci >>>>> shows the root complex, but no PCIe device behind it. >>>>> Tested on a i.MX6Q based tbs2910 board. >>>>> >>>>> For me it is not clear whether this fail to detect PCIe devices is >>>>> related to the patches in question, the reset timing, or something >>>>> else. Needs further investigation. >>>> Thanks for your kindly help to tests. >>>> Did you ever encounter the boot failure without this patch based on >>>> v7.2-rc1 >>>> or later? >>> Have not tested this. Unfortunately currently I have no access to my >>> tbs2910 test board. >>> I used a production system for this test here, but this is very >>> difficult to recover from boot hangs. >>>> After applied this patch, my i.MX6Q Sabresd board can boot up >>>> successfully. >>>> And the endpoint device can be detected as well. >>>> >>>> My Local commits: >>>> ad5939d49b268 (HEAD -> v7.2-rc2_pcie) PCI: imx6: Add runtime PM >>>> support for i.MX95 >>>> db7b15f198125 PCI: imx6: Update MPLLB bandwidth for i.MX95 PCIe Gen3 >>>> stability >>>> a26735515c076 PCI: imx6: Fix i.MX6Q/DL boot hang by separating PHY >>>> power and reference clock control >>>> d617eadf52a46 PCI: dwc: Add force_l2 flag for platforms requiring L2 >>>> entry without D3cold 8cdeaa50eae8d (tag: v7.2-rc2) Linux 7.2-rc2 >>> My commits (v7.2-rc2 plus my patch to enable MSIs for the endpoint >>> plus this patch discussed here): >>> 8cdeaa50eae8 Linux 7.2-rc2 >>> b62414d07e24 PCI: imx6: Keep Root Port MSI capability also for i.MX6Q >>> e8176c6a27ed PCI: imx6: Fix i.MX6Q/DL boot hang by separating PHY >>> power and reference clock control >>> >>> I'm not sure what your other mentioned patches are. >>>> Kernel logs: >>>> Starting kernel ... >>>> >>>> [=C2=A0=C2=A0=C2=A0 0.000000] Booting Linux on physical CPU 0x0 [=C2= =A0=C2=A0=C2=A0 0.000000] Linux >>>> version 7.2.0-rc2-00004-gad5939d49b26 >>>> (nxa08258@shlinux89) (arm-poky-linux-gnueabi-gcc (GCC) 15.2.0, GNU ld >>>> (GNU Binutils) 2.45.0.20250908) #38 SMP Tue Jul=C2=A0 7 02:36:46 UTC = 2026 >>>> ... >>>> root@imx6qpdlsolox:~# lspci >>>> 00:00.0 PCI bridge: Synopsys, Inc. DWC_usb3 / PCIe bridge (rev 01) >>>> 01:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network >>>> Connection >>> on linux-7.2-rc2 plus patches (see above): >>> root@matrix2:~# lspci >>> 00:00.0 PCI bridge: Synopsys, Inc. DWC_usb3 / PCIe bridge (rev 01) >>> >>> on linux-7.0 (not tested on 7.1): >>> root@matrix2:~# lspci >>> 00:00.0 PCI bridge: Synopsys, Inc. DWC_usb3 / PCIe bridge (rev 01) >>> 01:00.0 Multimedia controller: Philips Semiconductors SAA7160 (rev 02) >>> >>> I guess the new power-on/reset timing is not sufficient to init the >>> endpoint in time. >>> Did you reduce the time from powering up the PCIe slot to release of >>> PERST#? >>> There is a power switch on the tbs2910 board for the PCIe slot, not >>> sure if this is available also on SabreSD. > No, i.MX6Q Sabresd board doesn't have a power switch. Sorry, I was wrong here. On tbs2910 there is no separate 3V3 regulator=20 for the PCIe slot, on sabresd there is (reg_pcie, gpio3 19). At least there still is a difference, which could be a reason for the=20 different PCIe endpoint detection behavior on cold boot. Best Regards, Soeren >> I found out that the endpoint device is (often?) detected after reboot,= it is not >> (never) on cold boot. (linux-7.2-rc2 plus patches) Could also point to = timing >> problems of the slot power supply (or reset duration). >> Unfortunately I have only very limited time for testing. > Understand, thanks for your kindly help. > > Best Regards > Richard Zhu >>> Best regards, >>> Soeren >>>> Best Regards >>>> Richard Zhu >>>>> Regards, >>>>> Soeren