Hello, On Tue, 4 May 2010, Matthew Garrett wrote: > On Mon, May 03, 2010 at 04:37:22PM -0700, Kevin Hilman wrote: > > > Please forgive the ignorance of ACPI (in embedded, we thankfully live > > in magical world without ACPI) but doesn't that already happen with > > CPUidle and C-states? I think of CPUidle as basically runtime PM for > > the CPU. IOW, runtime PM manages the devices, CPUidle manages the CPU > > (via C-states), resulting in dynaimc PM for the entire system. What > > am I missing? > > ACPI doesn't provide any functionality for cutting power to most devices > other than shifting into full system suspend. ACPI may not, but the vast majority of ACPI systems are paired with PCI buses, or buses that emulate PCI buses; and PCI devices can implement device power control through the PCI Power Management capability. On my 2-year old ThinkPad, 13 of the 24 devices do, according to lspci. Many Linux device drivers already use PCI D-states to support a rudimentary form of runtime PM: [paul@twilight current]$ fgrep -r pci_set_power_state drivers/ | cut -d: -f1 | sort -u drivers/ata/ata_piix.c drivers/ata/libata-core.c drivers/ata/pata_macio.c drivers/block/cciss.c drivers/char/agp/amd64-agp.c drivers/char/agp/amd-k7-agp.c drivers/char/agp/ati-agp.c drivers/char/agp/nvidia-agp.c drivers/char/agp/sis-agp.c drivers/char/agp/via-agp.c drivers/firewire/ohci.c drivers/gpio/bt8xxgpio.c drivers/gpu/drm/i915/i915_dma.c drivers/gpu/drm/i915/i915_drv.c drivers/gpu/drm/nouveau/nouveau_drv.c drivers/gpu/drm/radeon/radeon_device.c drivers/gpu/drm/vmwgfx/vmwgfx_drv.c drivers/i2c/busses/i2c-i801.c drivers/ide/delkin_cb.c drivers/ide/sc1200.c drivers/ide/setup-pci.c drivers/ieee1394/ohci1394.c drivers/media/video/bt8xx/bttv-driver.c drivers/media/video/cx88/cx88-mpeg.c drivers/media/video/cx88/cx88-video.c drivers/media/video/saa7134/saa7134-core.c drivers/memstick/host/jmb38x_ms.c drivers/message/fusion/mptbase.c drivers/misc/cb710/core.c drivers/misc/tifm_7xx1.c drivers/mmc/host/sdhci-pci.c drivers/mmc/host/via-sdmmc.c drivers/net/3c59x.c drivers/net/8139cp.c drivers/net/8139too.c drivers/net/amd8111e.c drivers/net/atl1c/atl1c_main.c drivers/net/atl1e/atl1e_main.c drivers/net/atlx/atl1.c drivers/net/atlx/atl2.c drivers/net/benet/be_main.c drivers/net/e1000/e1000_main.c drivers/net/e1000e/netdev.c drivers/net/e100.c drivers/net/forcedeth.c drivers/net/igb/igb_main.c drivers/net/irda/vlsi_ir.c drivers/net/ixgbe/ixgbe_main.c drivers/net/jme.c drivers/net/ksz884x.c drivers/net/myri10ge/myri10ge.c drivers/net/ne2k-pci.c drivers/net/netxen/netxen_nic_main.c drivers/net/pci-skeleton.c drivers/net/pcnet32.c drivers/net/qlcnic/qlcnic_main.c drivers/net/qlge/qlge_main.c drivers/net/r8169.c drivers/net/sc92031.c drivers/net/sfc/efx.c drivers/net/sis900.c drivers/net/skge.c drivers/net/sky2.c drivers/net/smsc9420.c drivers/net/starfire.c drivers/net/tc35815.c drivers/net/tg3.c drivers/net/tulip/dmfe.c drivers/net/tulip/tulip_core.c drivers/net/tulip/uli526x.c drivers/net/typhoon.c drivers/net/via-rhine.c drivers/net/via-velocity.c drivers/net/vmxnet3/vmxnet3_drv.c drivers/net/wireless/adm8211.c drivers/net/wireless/airo.c drivers/net/wireless/ath/ath9k/pci.c drivers/net/wireless/hostap/hostap_pci.c drivers/net/wireless/ipw2x00/ipw2100.c drivers/net/wireless/ipw2x00/ipw2200.c drivers/net/wireless/iwlwifi/iwl-core.c drivers/net/wireless/orinoco/orinoco_pci.h drivers/net/wireless/p54/p54pci.c drivers/net/wireless/prism54/islpci_hotplug.c drivers/net/wireless/rt2x00/rt2x00pci.c drivers/net/wireless/rtl818x/rtl8180_dev.c drivers/parport/parport_serial.c drivers/pci/pci-acpi.c drivers/pci/pci.c drivers/pci/pci-driver.c drivers/pcmcia/yenta_socket.c drivers/scsi/3w-9xxx.c drivers/scsi/3w-sas.c drivers/scsi/aic7xxx/aic79xx_osm_pci.c drivers/scsi/aic7xxx/aic7xxx_osm_pci.c drivers/scsi/aic7xxx/aic7xxx_pci.c drivers/scsi/hpsa.c drivers/scsi/lpfc/lpfc_init.c drivers/scsi/megaraid/megaraid_sas.c drivers/scsi/mpt2sas/mpt2sas_scsih.c drivers/scsi/nsp32.c drivers/scsi/pm8001/pm8001_init.c drivers/scsi/pmcraid.c drivers/serial/8250_pci.c drivers/serial/serial_txx9.c drivers/spi/dw_spi_pci.c drivers/ssb/pcihost_wrapper.c drivers/staging/crystalhd/crystalhd_lnx.c drivers/staging/rt2860/pci_main_dev.c drivers/staging/rtl8187se/r8180_core.c drivers/staging/rtl8192e/r8192_pm.c drivers/staging/sm7xx/smtcfb.c drivers/staging/vt6655/device_main.c drivers/usb/gadget/langwell_udc.c drivers/video/arkfb.c drivers/video/aty/aty128fb.c drivers/video/aty/atyfb_base.c drivers/video/aty/radeon_pm.c drivers/video/i810/i810_main.c drivers/video/nvidia/nvidia.c drivers/video/s3fb.c drivers/video/savage/savagefb_driver.c drivers/video/vt8623fb.c drivers/virtio/virtio_pci.c - Paul _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
