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 3471724A076; Sun, 1 Mar 2026 01:18:29 +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=1772327909; cv=none; b=hC0fEkbS/wj+NbGr5Hl5kQ86bxhzfaCbkQbE3BX+jxxdVsy+f5SBvJhgHR0BeHALYiK7/1yLkq0pClgLAV8PfQ423B1E/cACQ3anN2TtXYoD9+UA6ITmuQ0TnTMAHZ3E+xfg9YK7Wm8NxXW8tkPcRhMVjpeAp3PBImgah9xojg8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772327909; c=relaxed/simple; bh=f1QwRXDsZKMS/2TuoSSMhTKDnJYmX/+DL2BMiCFg27w=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=pPryP5QcO0y33VBtSGFVg7sngbKX2sOjwxQ0neAuTkBI+kd0Nzvn4Iq0kdsQbvg+qPhV0tdIhVL8Ei2lhydDdqJbBB05FV+YAB6ZZPb2Toi+xS7KFAKgvXAITJGVliNptNanFyHsSvXYe+Ax1RtQ4yXeD9DCyme1hYz6QJfGPoU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DH3TsAnl; 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="DH3TsAnl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D0FAC19421; Sun, 1 Mar 2026 01:18:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772327909; bh=f1QwRXDsZKMS/2TuoSSMhTKDnJYmX/+DL2BMiCFg27w=; h=From:To:Cc:Subject:Date:From; b=DH3TsAnlqLQn8JmdK/p2ldNAgdyIoSVOVpbDWCiMttFhJS8oygTJegw6Cw6enVccF O0qK8UYOoHnNG3diXEdekpH3g0FJBNwmhw4DRwiQUS47+40W4pCQjR+Jp9cozM54pB r0ZyynOMz1sIRe2NAaJUTBFtBANOzBaOyuScyfb86e4esvRKixa+lL6IdhW6sMGkU2 3fQtvih3x/oi8DO5H8q9WR4BXFL0qIehc6pxM44Wr0K4PASjFH0oSXqdGBycPsEY5A WkqrRKxQSjJieO00EnxQhn4sRLoKp6w+hVbJbA6g6yG1GeDpC78M8FgAyhFSmEK0Wi KormKpW1sdpzA== From: Sasha Levin To: stable@vger.kernel.org, cassel@kernel.org Cc: Manivannan Sadhasivam , Shawn Lin , linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org Subject: FAILED: Patch "Revert "PCI: qcom: Don't wait for link if we can detect Link Up"" failed to apply to 6.12-stable tree Date: Sat, 28 Feb 2026 20:18:27 -0500 Message-ID: <20260301011827.1672839-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Hint: ignore X-stable: review Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From e9ce5b3804436301ab343bc14203a4c14b336d1b Mon Sep 17 00:00:00 2001 From: Niklas Cassel Date: Mon, 22 Dec 2025 07:42:10 +0100 Subject: [PATCH] Revert "PCI: qcom: Don't wait for link if we can detect Link Up" This reverts commit 36971d6c5a9a134c15760ae9fd13c6d5f9a36abb. While this fake hotplugging was a nice idea, it has shown that this feature does not handle PCIe switches correctly: pci_bus 0004:43: busn_res: can not insert [bus 43-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:43: busn_res: [bus 43-41] end is updated to 43 pci_bus 0004:43: busn_res: can not insert [bus 43] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:00.0: devices behind bridge are unusable because [bus 43] cannot be assigned for them pci_bus 0004:44: busn_res: can not insert [bus 44-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:44: busn_res: [bus 44-41] end is updated to 44 pci_bus 0004:44: busn_res: can not insert [bus 44] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:02.0: devices behind bridge are unusable because [bus 44] cannot be assigned for them pci_bus 0004:45: busn_res: can not insert [bus 45-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:45: busn_res: [bus 45-41] end is updated to 45 pci_bus 0004:45: busn_res: can not insert [bus 45] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:06.0: devices behind bridge are unusable because [bus 45] cannot be assigned for them pci_bus 0004:46: busn_res: can not insert [bus 46-41] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci_bus 0004:46: busn_res: [bus 46-41] end is updated to 46 pci_bus 0004:46: busn_res: can not insert [bus 46] under [bus 42-41] (conflicts with (null) [bus 42-41]) pci 0004:42:0e.0: devices behind bridge are unusable because [bus 46] cannot be assigned for them pci_bus 0004:42: busn_res: [bus 42-41] end is updated to 46 pci_bus 0004:42: busn_res: can not insert [bus 42-46] under [bus 41] (conflicts with (null) [bus 41]) pci 0004:41:00.0: devices behind bridge are unusable because [bus 42-46] cannot be assigned for them pcieport 0004:40:00.0: bridge has subordinate 41 but max busn 46 During the initial scan, PCI core doesn't see the switch and since the Root Port is not hot plug capable, the secondary bus number gets assigned as the subordinate bus number. This means, the PCI core assumes that only one bus will appear behind the Root Port since the Root Port is not hot plug capable. This works perfectly fine for PCIe endpoints connected to the Root Port, since they don't extend the bus. However, if a PCIe switch is connected, then there is a problem when the downstream busses starts showing up and the PCI core doesn't extend the subordinate bus number and bridge resources after initial scan during boot. The long term plan is to migrate this driver to the upcoming pwrctrl APIs that are supposed to handle this problem elegantly. Suggested-by: Manivannan Sadhasivam Signed-off-by: Niklas Cassel Signed-off-by: Manivannan Sadhasivam Tested-by: Shawn Lin Acked-by: Shawn Lin Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20251222064207.3246632-11-cassel@kernel.org --- drivers/pci/controller/dwc/pcie-qcom.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index 60373fe1362f8..e87ec6779d44f 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -1958,10 +1958,6 @@ static int qcom_pcie_probe(struct platform_device *pdev) platform_set_drvdata(pdev, pcie); - irq = platform_get_irq_byname_optional(pdev, "global"); - if (irq > 0) - pp->use_linkup_irq = true; - ret = dw_pcie_host_init(pp); if (ret) { dev_err(dev, "cannot initialize host\n"); @@ -1975,6 +1971,7 @@ static int qcom_pcie_probe(struct platform_device *pdev) goto err_host_deinit; } + irq = platform_get_irq_byname_optional(pdev, "global"); if (irq > 0) { ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, qcom_pcie_global_irq_thread, -- 2.51.0