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path: root/drivers/pci/pcie/aspm.c
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2009-11-06PCI ASPM: fix oops on root port removalKenji Kaneshige
Fix the following BUG_ON() problem reported by Alex Chiang. This problem happened when removing PCIe root port using PCI logical hotplug operation. The immediate cause of this problem is that the pointer to invalid data structure is passed to pcie_update_aspm_capable() by pcie_aspm_exit_link_state(). When pcie_aspm_exit_link_state() received a pointer to root port link, it unconfigures the root port link and frees its data structure at first. At this point, there are not links to configure under the root port and the data structure for root port link is already freed. So pcie_aspm_exit_link_state() must not call pcie_update_aspm_capable() and pcie_config_aspm_path(). This patch fixes the problem by changing pcie_aspm_exit_link_state() not to call pcie_update_aspm_capable() and pcie_config_aspm_path() if the specified link is root port link. ------------[ cut here ]------------ kernel BUG at drivers/pci/pcie/aspm.c:606! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC last sysfs file: /sys/devices/pci0000:40/0000:40:13.0/remove CPU 1 Modules linked in: shpchp Pid: 9345, comm: sysfsd Not tainted 2.6.32-rc5 #98 ProLiant DL785 G6 RIP: 0010:[<ffffffff811df69b>] [<ffffffff811df69b>] pcie_update_aspm_capable+0x15/0xbe RSP: 0018:ffff88082a2f5ca0 EFLAGS: 00010202 RAX: 0000000000000e77 RBX: ffff88182cc3e000 RCX: ffff88082a33d006 RDX: 0000000000000001 RSI: ffffffff811dff4a RDI: ffff88182cc3e000 RBP: ffff88082a2f5cc0 R08: ffff88182cc3e000 R09: 0000000000000000 R10: ffff88182fc00180 R11: ffff88182fc00198 R12: ffff88182cc3e000 R13: 0000000000000000 R14: ffff88182cc3e000 R15: ffff88082a2f5e20 FS: 00007f259a64b6f0(0000) GS:ffff880864600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 00007feb53f73da0 CR3: 000000102cc94000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process sysfsd (pid: 9345, threadinfo ffff88082a2f4000, task ffff88082a33cf00) Stack: ffff88182cc3e000 ffff88182cc3e000 0000000000000000 ffff88082a33cf00 <0> ffff88082a2f5cf0 ffffffff811dff52 ffff88082a2f5cf0 ffff88082c525168 <0> ffff88402c9fd2f8 ffff88402c9fd2f8 ffff88082a2f5d20 ffffffff811d7db2 Call Trace: [<ffffffff811dff52>] pcie_aspm_exit_link_state+0xf5/0x11e [<ffffffff811d7db2>] pci_stop_bus_device+0x76/0x7e [<ffffffff811d7d67>] pci_stop_bus_device+0x2b/0x7e [<ffffffff811d7e4f>] pci_remove_bus_device+0x15/0xb9 [<ffffffff811dcb8c>] remove_callback+0x29/0x3a [<ffffffff81135aeb>] sysfs_schedule_callback_work+0x15/0x6d [<ffffffff81072790>] worker_thread+0x19d/0x298 [<ffffffff8107273b>] ? worker_thread+0x148/0x298 [<ffffffff81135ad6>] ? sysfs_schedule_callback_work+0x0/0x6d [<ffffffff810765c0>] ? autoremove_wake_function+0x0/0x38 [<ffffffff810725f3>] ? worker_thread+0x0/0x298 [<ffffffff8107629e>] kthread+0x7d/0x85 [<ffffffff8102eafa>] child_rip+0xa/0x20 [<ffffffff8102e4bc>] ? restore_args+0x0/0x30 [<ffffffff81076221>] ? kthread+0x0/0x85 [<ffffffff8102eaf0>] ? child_rip+0x0/0x20 Code: 89 e5 8a 50 48 31 c0 c0 ea 03 83 e2 07 e8 b2 de fe ff c9 48 98 c3 55 48 89 e5 41 56 49 89 fe 41 55 41 54 53 48 83 7f 10 00 74 04 <0f> 0b eb fe 48 8b 05 da 7d 63 00 4c 8d 60 e8 4c 89 e1 eb 24 4c RIP [<ffffffff811df69b>] pcie_update_aspm_capable+0x15/0xbe RSP <ffff88082a2f5ca0> ---[ end trace 6ae0f65bdeab8555 ]--- Reported-by: Alex Chiang <achiang@hp.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Tested-by: Alex Chiang <achiang@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-17PCI ASPM: support L1 onlyKenji Kaneshige
The definition of the ASPM support field in the Link Capabilities Register had been changed by the "ASPM optionality ECN" as follows: <Before> 00b Reserved 01b L0s Supported 10b Reserved 11b L0s and L1 Supported <After> 00b No ASPM Support 01b L0s Supported 10b L1 Supported 11b L0s and L1 Supported Current linux ASPM driver doesn't enable ASPM if the support field is 00b or 10b. So there is no impact about 00b. But current linux ASPM driver doesn't enable L1 if the support field is 10b. With this patch, 10b (L1 support) is handled properly. Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-09PCI ASPM: support per direction l0s managementKenji Kaneshige
The L0s state can be managed separately for each direction (upstream direction and downstream direction) of the link. But in the current implementation, those are mixed up. With this patch, L0s for each direction are managed separately. To maintain three states (upstream direction L0s, downstream L0s and L1), 'aspm_support', 'aspm_enabled', 'aspm_capable', 'aspm_disable' and 'aspm_default' fields in struct pcie_link_state are changed to 3-bit from 2-bit. The 'latency' field is separated to two 'latency_up' and 'latency_dw' fields to maintain exit latencies for each direction of the link. For L0, 'latency_up.l0' and 'latency_dw.l0' are used to configure upstream direction L0s and downstream direction L0s respectively. For L1, larger value of 'latency_up.l1' and 'latency_dw.l1' is considered as L1 exit latency. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-09PCI ASPM: support partial aspm enablementKenji Kaneshige
In the current implementation, ASPM L0s/L1 is disabled for all links in the hierarchy if one of the link doesn't meet latency requirement. But we can partially enable ASPM L0s/L1 on sub-tree in the hierarchy. This patch allows partial L0s/L1 enablement in the hierarchy. And it also reduce the calculation cost of ASPM configuration very much. In the previous implementation, all links were enabled with the same state. With this patch, enabled state for each link is determined simply as follows (the 'requested' is from policy_to_aspm_state()). enabled = requested & (link->aspm_capable & link->aspm_disable) Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-09PCI ASPM: introduce capable flagKenji Kaneshige
Introduce 'aspm_capable' field to maintain the capable ASPM setting of the link. By the 'aspm_capable', we don't need to recheck latency every time ASPM policy is changed. Each bit in 'aspm_capable' is associated to ASPM state (L0S/L1). The bit is set if the associated ASPM state is supported by the link and it satisfies the latency requirement (i.e. exit latency < endpoint acceptable latency). The 'aspm_capable' is updated when - an endpoint device is added (boot time or hot-plug time) - an endpoint device is removed (hot-unplug time) - PCI power state is changed. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-09PCI ASPM: introduce disable flagKenji Kaneshige
Introduce 'aspm_disable' flag to manage disabled ASPM state more robust way. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-09PCI ASPM: fix possible null pointer dereferenceKenji Kaneshige
Fix possible NULL dereference in pcie_aspm_exit_link_state(). This patch also cleanup some code. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-09PCI ASPM: remove redundant list checkKenji Kaneshige
Remove the following check in __pcie_aspm_config_link() because it nerver be true. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-09-09PCI ASPM: do not clear enabled field by support fieldKenji Kaneshige
We must not clear bits in 'aspm_enabled' using 'aspm_support', or 'aspm_enabled' and 'aspm_default' might be different from the actual state. In addtion, 'aspm_default' should be intialized even if 'aspm_support' is 0. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: remove get_root_port_linkKenji Kaneshige
By having a pointer to the root port link, we can remove loops in get_root_port_link() to search the root port link. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup pcie_aspm_sanity_checkKenji Kaneshige
Minor cleanup for pcie_aspm_sanity_check(). Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: remove has_switch fieldKenji Kaneshige
We don't need the 'has_switch' field in the struct pcie_link_state. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup calc_Lx_latencyKenji Kaneshige
Cleanup for calc_L0S_latency() and calc_L1_latency(). - Separate exit latency and acceptable latency calculation. - Some minor cleanups. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup pcie_aspm_get_cap_deviceKenji Kaneshige
Minor cleanup for pcie_aspm_get_cap_device(). Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup clkpm checksKenji Kaneshige
In the current ASPM implementation, callers of pcie_set_clock_pm() check Clock PM capability of the link or current Clock PM state of the link. This check should be done in pcie_set_clock_pm() itself. This patch moves those checks into pcie_set_clock_pm(). It also introduces pcie_set_clkpm_nocheck() that is equivalent to old pcie_set_clock_pm(), for the caller who wants to change Clocl PM state regardless of the Clock PM capability or current Clock PM state. In addition, this patch changes the function name from pcie_set_clock_pm() to pcie_set_clkpm() for consistency. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup __pcie_aspm_check_state_oneKenji Kaneshige
Clean up and simplify __pcie_aspm_check_state_one(). Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup initializationKenji Kaneshige
Clean up ASPM initialization by refactoring some functionality, renaming functions, and moving things around. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup change input argument of aspm functionsKenji Kaneshige
In the current ASPM implementation, there are many functions that take a pointer to struct pci_dev corresponding to the upstream component of the link as a parameter. But, since those functions handle PCI express link state, a pointer to struct pcie_link_state is more suitable than a pointer to struct pci_dev. Changing a parameter to a pointer to struct pcie_link_state makes ASPM code much simpler and easier to read. This patch also contains some minor cleanups. This patch doesn't have any functional change. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup misc in struct pcie_link_stateKenji Kaneshige
Cleanup for some fields in pcie_link_state. - Add comments. - make "downstream_has_switch" field 1-bit. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup clkpm state in struct pcie_link_stateKenji Kaneshige
The "clk_pm_capable", "clk_pm_enable" and "bios_clk_state" fields in the struct pcie_link_state only take 1-bit value. So those fields don't need to be defined as unsigned int. This patch makes those fields 1-bit, and cleans up some related code. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup latency field in struct pcie_link_stateKenji Kaneshige
Clean up latency related data structures for ASPM. - Introduce struct acpi_latency for exit latency and acceptable latency management. With this change, struct endpoint_state is no longer needed. - We don't need to hold both upstream latency and downstream latency in the current implementation. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: cleanup aspm state field in struct pcie_link_stateKenji Kaneshige
The "support_state", "enabled_state" and "bios_aspm_state" fields in the struct pcie_link_state take 2-bit value. So those fields don't need to be defined as unsigned int. This patch makes those fields 2-bit, and cleans up some related code. Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-18PCI ASPM: fix typo in struct pcie_link_stateKenji Kaneshige
Fix a typo in struct pcie_link_state. The "sibiling" field in the struct pcie_link_state should be "sibling". Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-11PCI: disable ASPM on VIA root-port-under-bridge configurationsShaohua Li
VIA has a strange chipset, it has root port under a bridge. Disable ASPM for such strange chipset. Cc: stable@kernel.org Tested-by: Wolfgang Denk <wd@denx.de> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-02-04PCI: properly clean up ASPM link state on device removeAlex Chiang
We only want to disable ASPM when the last function is removed from the parent's device list. We determine this by checking to see if the parent's device list is completely empty. Unfortunately, we never hit that code because the parent is considered an upstream port, and never had an ASPM link_state associated with it. The early check for !link_state causes us to return early, we never discover that our device list is empty, and thus we never remove the downstream ports' link_state nodes. Instead of checking to see if the parent's device list is empty, we can check to see if we are the last device on the list, and if so, then we know that we can clean up properly. Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-01-07PCI: Use msleep instead of cpu_relax during ASPM link retrainingAndrew Patterson
The cpu_relax() function can be a noop on certain architectures like IA-64 when CPU threads are disabled, so use msleep instead during link retraining busy/wait loop. Introduce define LINK_RETRAIN_TIMEOUT instead of hard-coding timeout in pcie_aspm_configure_common_clock. Use time_after() to avoid jiffy wraparound when checking for expired timeout. After timeout expires, recheck link status register link training bit instead of checking for expired timeout to avoid possible false positive. Note that Matthew Wilcox came up with the first rough version of this patch. Reviewed-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Andrew Patterson <andrew.patterson@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-01-07PCI: keep ASPM link state consistent throughout PCIe hierarchyShaohua Li
In a PCIe hierarchy with a switch present, if the link state of an endpoint device is changed, we must check the whole hierarchy from the endpoint device to root port, and for each link in the hierarchy, the new link state should be configured. Previously, the implementation checked the state but forgot to configure the links between root port to switch. Fixes Novell bz #448987. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Tested-by: Andrew Patterson <andrew.patterson@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-01-07ACPI/PCI: PCIe ASPM _OSC support capabilities called when root bridge addedAndrew Patterson
The _OSC capabilities OSC_ACTIVE_STATE_PWR_SUPPORT and OSC_CLOCK_PWR_CAPABILITY_SUPPORT are set when the root bridge is added with pci_acpi_osc_support(), so we no longer need to do it in the ASPM driver. Also add the function pcie_aspm_enabled, which returns true if pcie_aspm=off is not on the kernel command-line. Signed-off-by: Andrew Patterson <andrew.patterson@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-12-09PCIe: ASPM: Break out of endless loop waiting for PCI config bits to switchThomas Renninger
Makes a Compaq 6735s boot reliably again. It used to hang in the loop on some boots. Give the link one second to train, otherwise break out of the loop and reset the previously set clock bits. Cc: stable@vger.kernel.org Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-10-20PCI: probing debug message uniformizationVincent Legoll
This patch uniformizes PCI probing debug boot messages with dev_printk() intead of manual printk() It changes adress range output from [%llx, %llx] to [%#llx-%#llx], like in pci_request_region(). For example, it goes from the mixed-style: PCI: 0000:00:1b.0 reg 10 64bit mmio: [f4280000, f4283fff] pci 0000:00:1b.0: PME# supported from D0 D3hot D3cold to uniform: pci 0000:00:1b.0: reg 10 64bit mmio: [0xf4280000-0xf4283fff] pci 0000:00:1b.0: PME# supported from D0 D3hot D3cold This patch has been runtime tested, boot log messages diffed, everything looks OK. Acked-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Vincent Legoll <vincent.legoll@gmail.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-09-16PCI: Fix pcie_aspm=forceSitsofe Wheeler
pcie_aspm=force did not work because aspm_force was being double negated leading to the sanity check failing. Moving a bracket should fix this. Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-07-28PCI: add an option to allow ASPM enabled forciblyShaohua Li
A new option, pcie_aspm=force, will force ASPM to be enabled, even on system with PCIe 1.0 devices. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-07-28PCI: disable ASPM on pre-1.1 PCIe devicesShaohua Li
Disable ASPM on pre-1.1 PCIe devices, as many of them don't implement it correctly. Tested-by: Jack Howarth <howarth@bromo.msbb.uc.edu> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-07-28PCI: disable ASPM per ACPI FADT settingShaohua Li
The ACPI FADT table includes an ASPM control bit. If the bit is set, do not enable ASPM since it may indicate that the platform doesn't actually support the feature. Tested-by: Jack Howarth <howarth@bromo.msbb.uc.edu> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-05-21PCI: don't enable ASPM on devices with mixed PCIe/PCI functionsShaohua Li
The Slot 03:00.* of JMicron controller has two functions, but one is PCIE endpoint the other isn't PCIE device, very strange. PCIE spec defines all functions should have the same config for ASPM, so disable ASPM for the whole slot in this case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-04-20PCI: add PCI Express ASPM supportShaohua Li
PCI Express ASPM defines a protocol for PCI Express components in the D0 state to reduce Link power by placing their Links into a low power state and instructing the other end of the Link to do likewise. This capability allows hardware-autonomous, dynamic Link power reduction beyond what is achievable by software-only controlled power management. However, The device should be configured by software appropriately. Enabling ASPM will save power, but will introduce device latency. This patch adds ASPM support in Linux. It introduces a global policy for ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control it. The interface can be used as a boot option too. Currently we have below setting: -default, BIOS default setting -powersave, highest power saving mode, enable all available ASPM state and clock power management -performance, highest performance, disable ASPM and clock power management By default, the 'default' policy is used currently. In my test, power difference between powersave mode and performance mode is about 1.3w in a system with 3 PCIE links. Note: some devices might not work well with aspm, either because chipset issue or device issue. The patch provide API (pci_disable_link_state), driver can disable ASPM for specific device. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-02-02Revert "PCI: PCIE ASPM support"Greg Kroah-Hartman
This reverts commit 6c723d5bd89f03fc3ef627d50f89ade054d2ee3b. It caused build errors on non-x86 platforms, config file confusion, and even some boot errors on some x86-64 boxes. All around, not quite ready for prime-time :( Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-02-01PCI: PCIE ASPM supportShaohua Li
PCI Express ASPM defines a protocol for PCI Express components in the D0 state to reduce Link power by placing their Links into a low power state and instructing the other end of the Link to do likewise. This capability allows hardware-autonomous, dynamic Link power reduction beyond what is achievable by software-only controlled power management. However, The device should be configured by software appropriately. Enabling ASPM will save power, but will introduce device latency. This patch adds ASPM support in Linux. It introduces a global policy for ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control it. The interface can be used as a boot option too. Currently we have below setting: -default, BIOS default setting -powersave, highest power saving mode, enable all available ASPM state and clock power management -performance, highest performance, disable ASPM and clock power management By default, the 'default' policy is used currently. In my test, power difference between powersave mode and performance mode is about 1.3w in a system with 3 PCIE links. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>