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 BB2C2354AF4; Tue, 11 Nov 2025 10:51:23 +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=1762858283; cv=none; b=WpOAF7P1bgJOhesv9TDEICGmCf9hc5TuayPnBUClcTuo5eYIImz5ArzOdK9ruQLJOsZd75AO2aLoAXf+fzf1kAEFAarqwqk3XJrf6jlvYOjoBDgoycntSY+zgL3E5sJNYsgHoaICoM9abBeKQBEhvsA0oYWDyuyAq5sY0+ulTfo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762858283; c=relaxed/simple; bh=KQFcltA1YTOW8wFzTg1A74xu3BPlLmfOXmJrG/cc1Sg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X85RveTNLzZilAqiY5tHyNGesG2mD6oRA2+zfTgfqzVKTm67CIgTcfNKBObBcM75u4uhJE8uR6JtxQiji4vMf2znguZOM5o1jof2VfpMAAo+2uub0tv/+rVzTrj4Q2GTnvJYswc6qSoblfZqKdYbDED7pCpEQUHAH26m2cjDHXE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MUuU0J24; 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="MUuU0J24" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C185CC4CEFB; Tue, 11 Nov 2025 10:51:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762858283; bh=KQFcltA1YTOW8wFzTg1A74xu3BPlLmfOXmJrG/cc1Sg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MUuU0J24pljE3LDduRMqg2DDOn6BwPGb+n8YS+/7V/FNN5vam/OKzFLVSZrl9a68n hGRb/c1JWfvbdaeYfNLiFt0vxNodVxMD1n0zqKq0b7C8Ug+Wm9djMNvFDjiihr85ip SRB1/SPpEUkDncedSYq1ygqqczEi2XKmEvZwj0YJPcRno3CgzR7HZc2CsPZtSIwbVG r8WsAnqMCgcuckObLYwZixSglxTBYqnyGhJw2RCVOBU9m/c2G/nnQVv9VBpPHRDA8Z hNYaODtu5g96xjEI3Nl/eZSVp2kfSgfgBjBRAD9FqULvx6t3kgotlGniY/lH5vpFlA uh7hGEPQ+e/gQ== From: Niklas Cassel To: Manivannan Sadhasivam , Lorenzo Pieralisi , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , Rob Herring , Bjorn Helgaas Cc: Shawn Lin , FUKAUMI Naoki , Krishna chaitanya chundru , Niklas Cassel , stable@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH 3/6] Revert "PCI: qcom: Don't wait for link if we can detect Link Up" Date: Tue, 11 Nov 2025 11:51:03 +0100 Message-ID: <20251111105100.869997-11-cassel@kernel.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251111105100.869997-8-cassel@kernel.org> References: <20251111105100.869997-8-cassel@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3885; i=cassel@kernel.org; h=from:subject; bh=KQFcltA1YTOW8wFzTg1A74xu3BPlLmfOXmJrG/cc1Sg=; b=owGbwMvMwCV2MsVw8cxjvkWMp9WSGDKFRUVvXN69fEPn6e4rOW0czzjfW7BkFkxJ6iznLRffd e1eLEtaRykLgxgXg6yYIovvD5f9xd3uU44r3rGBmcPKBDKEgYtTACZid5Xhf8qTV3I67fq8l1T/ 3DjA4F1kvXT/t/A3wT6HVS43qR1s9mJk2L9TaovrWl+J6ItT7t8OYXrxR6aIW9r31Z9QjpPv0k6 v4gAA X-Developer-Key: i=cassel@kernel.org; a=openpgp; fpr=5ADE635C0E631CBBD5BE065A352FE6582ED9B5DA Content-Transfer-Encoding: 8bit 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 after initial scan during boot. The long term plan is to migrate this driver to the pwrctrl framework, once it adds proper support for powering up and enumerating PCIe switches. Cc: stable@vger.kernel.org Suggested-by: Manivannan Sadhasivam Signed-off-by: Niklas Cassel --- 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 c48a20602d7f..70c0ae8b7523 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -1927,10 +1927,6 @@ 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"); @@ -1944,6 +1940,7 @@ 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, -- 2.51.1