From nobody Fri Jul 24 22:20:02 2026 Received: from mail-pf1-f179.google.com (mail-pf1-f179.google.com [209.85.210.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF6724582CA for ; Wed, 22 Jul 2026 23:13:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.179 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784762019; cv=none; b=Z/KMzr/Ck6WBnwrGBPyqOZvERLqyWg1l36AHPxmxcmSiX/4qcFiQvH5Di1uUZkiDP8m4mvODaAoR7EF41MCmZkf97kbLSf3jn+ZGJitzct3tost/25TltnDcbSmN3WnakhttGnq6Kxuc3Zn/BxXLHzA7pumqiumxeS9DTQhNjsg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784762019; c=relaxed/simple; bh=UvZsCO1GmPNqzk7wzdyGpdQ11lkDL/idmR9vFBMt9ZI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=T8IANM/R7ETbsicUx/ihvXE+JaDap+DaGR18FnAAaJPqQfNEGphlolL6nAn4FoZUiFAFkjQybGQHjDSQiuJ6PbnqSE8n7st/Gqx2nja9txItAM1bt2uawdBnp98j2NbvIovMPm5X4H5kruBXLFjHxPiyRG66EqqE2gZqVFh8KFs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=UcR4281s; arc=none smtp.client-ip=209.85.210.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="UcR4281s" Received: by mail-pf1-f179.google.com with SMTP id d2e1a72fcca58-84536ecfc5bso17975b3a.2 for ; Wed, 22 Jul 2026 16:13:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1784762017; x=1785366817; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=T8SbK/NCKyIaBwC1Thbd7+4CLdIOgq9KZMPr78i26/Y=; b=UcR4281swcGqQDX7RM8G0GiSweW0/XOWK5YE2HFboR66fIKXd1wx3cb4Dax1n/FXRh Y54RmdROIrOMOzsqYUntIPxJmlXTAQwI/xaTc4yhj50W3lFcDOirTteBHNXDmPrbvkCX 9vKAj3ws1mpNaS21TlL3aG/wnil5EiYcTSPYg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784762017; x=1785366817; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=T8SbK/NCKyIaBwC1Thbd7+4CLdIOgq9KZMPr78i26/Y=; b=ImCQEo3pm2zJ+gI2sDCZGEaA1SiGanUFbsN4qR5BoaamZEF6nI2sZLRIlHLPiVSL3L ydDdQB7HmT54FSP1gAkGBBXEj7aD4YPZVllzwd9tmbo8G/6hgporFGZXZtodmuWrnqKU 2h6JsPFBwDEkAGiRtMVl8i6WbIW1hCvp50RRcDFtrf9PUkRZxdxqYqfjh9+9LmsIq+gx oRxfB7GVSo0zmeiSYpC1NfY7cqdlqbusWDsloZt2Pradzb7n9MO2PMflpbuWNiff1xJ1 zW3lkXAz0oMMY+OTxubtBYSIVyf5fPZHaF7k165hYz5lHBdQNnsvkfpoYIYuUiDxMT2Y Kg9Q== X-Forwarded-Encrypted: i=1; AHgh+RoZkGZIhSardMShJ0H7fSA3sx5Af9GLJmzsdgqUVhrvA4B1IGJsigHp1O7DLAkfd+tETbGcRmUC0kmFxYE=@vger.kernel.org X-Gm-Message-State: AOJu0YzX5vFjRYFLXh5xLqtiVzVXbUsi8giybohdBLjDvj4E9wXgZ8Dt Ehf5rI4JEUkMCX4EQEXpYJrW2MI2Qoem9qm4MCMqutoEDcbtVYgxd8cShdCdQxpAwA== X-Gm-Gg: AR+sD13n/Hh/7z5/52x8Bk1+5UtF+522REy1B6rL4blruxgqmViA6Rd1Uy5qGs+vBVP TxsN3SMb9JewBAbM2jg610xbQGUGY1q9ImYVMtFeYD9vyy14oOw7qPPzooouwVLYLCSszt3omtF Onx2f9tCEzBcTIqp20OdSLNLS9KXtD0cVf9q7lk2h0w8A5M9jB25rzS9uFOtqBkEpbHNFFAp10H q97V3cpY/qsGa86E/SsAyDA0B396yOSUgIIdZ+mdTFHFI1wS1iXXJLLa2D0SXahumr3e64wUQa8 Jb/3DulRD8ABjEQPjsCTSkRkgBJLde/kfo2HDJmuHrmDgKMIipnPM2gLFGtvG8aM9OtBy0tW/SU /FBOuiNiaaKNOlZhu59cBRVVmT7spQWfcl3teMYCKDlyqfGT1bm6Eod7975iTL8sdZIdC16nT2Y 28vFA9sEp6jwFu6U6SKT1dGuoldovjCWdkpLMINaRU57e4nFfVcmA= X-Received: by 2002:a05:6a21:7a96:b0:3c0:9c19:65b9 with SMTP id adf61e73a8af0-3c44b26f282mr511168637.65.1784762017184; Wed, 22 Jul 2026 16:13:37 -0700 (PDT) Received: from localhost ([2a00:79e0:2e7c:8:f3fd:a899:78ad:64d4]) by smtp.gmail.com with UTF8SMTPSA id 5a478bee46e88-3147df09ac0sm11650219eec.16.2026.07.22.16.13.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Jul 2026 16:13:36 -0700 (PDT) From: Brian Norris To: Bjorn Helgaas Cc: Manivannan Sadhasivam , linux-pci@vger.kernel.org, David Matlack , Lukas Wunner , linux-kernel@vger.kernel.org, Brian Norris Subject: [PATCH v4] PCI/portdrv: Allow probing even without child services Date: Wed, 22 Jul 2026 16:09:42 -0700 Message-ID: <20260722160942.v4.1.I5fd5d83f518681b3949d8ab2f16ba8244fd3e774@changeid> X-Mailer: git-send-email 2.55.0.229.g6434b31f56-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The PCIe port driver fails to probe if it finds no child services, presumably under the assumption that the driver is not useful in that case. However, the driver *can* still be useful for power management support -- namely, it still configures the port for runtime PM / D3, which may be important for allowing a bridge to enter low power modes. Thus, allow probe to succeed even if no IRQs and no child services are available. This also mirrors existing behavior for ports that don't support any portdrv services (PCIe hotplug, AER, DPC, PME, bwctrl), where we'd also probe successfully. This change is a bit more important after commit f5cd8a929c82 ("PCI: dwc: Remove MSI/MSIX capability for Root Port if iMSI-RX is used as MSI controller"), because it's common for some DWC-based systems to: 1. have only the "aer" and "pcie_pme" port services available and 2. not define legacy INTx interrupts properly in their device tree. After commit f5cd8a929c82, such systems may fail pcie_init_service_irqs() and so exit with -ENODEV. Link: https://lore.kernel.org/all/nyada24tqwlkzdceyoxbzitzygvp4elvj5oajnqdw= b33xkcdwk@76vnrx45fsfd/ Signed-off-by: Brian Norris Reviewed-by: Lukas Wunner --- Changes in v4: * Between sashiko-bot / Mani / me / Bjorn, we agreed that deferring pci_set_master() may cause us to drop some MSIs: https://lore.kernel.org/all/af574zaysKnXjx15@google.com/ So we revert to the v2 approach, with some small changes * Address some of Lukas's review comments: https://lore.kernel.org/all/al68lFtbq_Q4RCL2@google.com/ Specifically: - ensure pcie_device_init() return code is checked - release IRQs (pci_free_irq_vectors()) when no services registered properly * Borrow some of Bjorn's commit message tweaks Changes in v3: * Defer pci_set_master() until we really know we have some child service Changes in v2: * Clear master when we have no child services drivers/pci/pcie/portdrv.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c index 2d6aa488fe7b..18ee190acc6e 100644 --- a/drivers/pci/pcie/portdrv.c +++ b/drivers/pci/pcie/portdrv.c @@ -330,7 +330,7 @@ static int pcie_device_init(struct pci_dev *pdev, int s= ervice, int irq) */ static int pcie_port_device_register(struct pci_dev *dev) { - int status, capabilities, i, nr_service; + int status, capabilities, i; int irqs[PCIE_PORT_DEVICE_MAXSERVICES]; =20 /* Enable PCI Express port device */ @@ -355,29 +355,29 @@ static int pcie_port_device_register(struct pci_dev *= dev) if (status) { capabilities &=3D PCIE_PORT_SERVICE_HP; if (!capabilities) - goto error_disable; + goto out; } =20 /* Allocate child services if any */ - status =3D -ENODEV; - nr_service =3D 0; for (i =3D 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) { int service =3D 1 << i; if (!(capabilities & service)) continue; - if (!pcie_device_init(dev, service, irqs[i])) - nr_service++; + if (pcie_device_init(dev, service, irqs[i])) + capabilities &=3D ~service; } - if (!nr_service) - goto error_cleanup_irqs; =20 - return 0; +out: + /* + * With no child services, we shouldn't need bus mastering or any IRQ + * vectors we allocated. + */ + if (!capabilities) { + pci_free_irq_vectors(dev); + pci_clear_master(dev); + } =20 -error_cleanup_irqs: - pci_free_irq_vectors(dev); -error_disable: - pci_disable_device(dev); - return status; + return 0; } =20 typedef int (*pcie_callback_t)(struct pcie_device *); --=20 2.55.0.229.g6434b31f56-goog