PCI: Set device power state to PCI_D0 for device without native PM support - linux-dev - Linux kernel development work

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author	Ajaykumar Hotchandani <ajaykumar.hotchandani@oracle.com>	2011-12-12 13:57:36 +0530
committer	Jesse Barnes <jbarnes@virtuousgeek.org>	2011-12-14 08:26:42 -0800
commit	b51306c63449d7f06ffa689036ba49eb46e898b5 (patch)
tree	6f3ad6817681c1ee2a7d7abc86d85695564924ea /kernel/debug
parent	PCI hotplug: Always allow acpiphp to handle non-PCIe bridges (diff)

PCI: Set device power state to PCI_D0 for device without native PM support

During test of one IB card with guest VM, found that, msi is not initialized properly. It turns out __write_msi_msg will do nothing if device current_state is not PCI_D0. And, that pci device does not have pm_cap in guest VM. There is an error in setting of power state to PCI_D0 in pci_enable_device(), but error is not returned for this. Following is code flow: pci_enable_device() --> __pci_enable_device_flags() --> do_pci_enable_device() --> pci_set_power_state() --> __pci_start_power_transition() We have following condition inside __pci_start_power_transition(): if (platform_pci_power_manageable(dev)) { error = platform_pci_set_power_state(dev, state); if (!error) pci_update_current_state(dev, state); } else { error = -ENODEV; /* Fall back to PCI_D0 if native PM is not supported */ if (!dev->pm_cap) dev->current_state = PCI_D0; } Here, from platform_pci_set_power_state(), acpi_pci_set_power_state() is getting called and that is failing with ENODEV because of following condition: if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0",&tmp))) return -ENODEV; Because of that, pci_update_current_state() is not getting called. With this patch, if device power state can not be set via platform_pci_set_power_state and that device does not have native pm support, then PCI device power state will be set to PCI_D0. -v2: This also reverts 47e9037ac16637cd7f12b8790ea7ce6680e42168, as it's not needed after this change. Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Ajaykumar Hotchandani<ajaykumar.hotchandani@oracle.com> Signed-off-by: Yinghai Lu<yinghai.lu@oracle.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Diffstat (limited to 'kernel/debug')

0 files changed, 0 insertions, 0 deletions

// SPDX-License-Identifier: GPL-2.0 /* Multipath TCP * * Copyright (c) 2019, Tessares SA. */ #include <linux/sysctl.h> #include <net/net_namespace.h> #include <net/netns/generic.h> #include "protocol.h" #define MPTCP_SYSCTL_PATH "net/mptcp" static int mptcp_pernet_id; struct mptcp_pernet { struct ctl_table_header *ctl_table_hdr; int mptcp_enabled; }; static struct mptcp_pernet *mptcp_get_pernet(struct net *net) { return net_generic(net, mptcp_pernet_id); } int mptcp_is_enabled(struct net *net) { return mptcp_get_pernet(net)->mptcp_enabled; } static struct ctl_table mptcp_sysctl_table[] = { { .procname = "enabled", .maxlen = sizeof(int), .mode = 0644, /* users with CAP_NET_ADMIN or root (not and) can change this * value, same as other sysctl or the 'net' tree. */ .proc_handler = proc_dointvec, }, {} }; static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet) { pernet->mptcp_enabled = 1; } static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet) { struct ctl_table_header *hdr; struct ctl_table *table; table = mptcp_sysctl_table; if (!net_eq(net, &init_net)) { table = kmemdup(table, sizeof(mptcp_sysctl_table), GFP_KERNEL); if (!table) goto err_alloc; } table[0].data = &pernet->mptcp_enabled; hdr = register_net_sysctl(net, MPTCP_SYSCTL_PATH, table); if (!hdr) goto err_reg; pernet->ctl_table_hdr = hdr; return 0; err_reg: if (!net_eq(net, &init_net)) kfree(table); err_alloc: return -ENOMEM; } static void mptcp_pernet_del_table(struct mptcp_pernet *pernet) { struct ctl_table *table = pernet->ctl_table_hdr->ctl_table_arg; unregister_net_sysctl_table(pernet->ctl_table_hdr); kfree(table); } static int __net_init mptcp_net_init(struct net *net) { struct mptcp_pernet *pernet = mptcp_get_pernet(net); mptcp_pernet_set_defaults(pernet); return mptcp_pernet_new_table(net, pernet); } /* Note: the callback will only be called per extra netns */ static void __net_exit mptcp_net_exit(struct net *net) { struct mptcp_pernet *pernet = mptcp_get_pernet(net); mptcp_pernet_del_table(pernet); } static struct pernet_operations mptcp_pernet_ops = { .init = mptcp_net_init, .exit = mptcp_net_exit, .id = &mptcp_pernet_id, .size = sizeof(struct mptcp_pernet), }; void __init mptcp_init(void) { mptcp_proto_init(); if (register_pernet_subsys(&mptcp_pernet_ops) < 0) panic("Failed to register MPTCP pernet subsystem.\n"); } #if IS_ENABLED(CONFIG_MPTCP_IPV6) int __init mptcpv6_init(void) { int err; err = mptcp_proto_v6_init(); return err; } #endif


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