Messages in this thread | | | Date | Tue, 22 Jan 2008 14:58:06 -0800 | From | Greg KH <> | Subject | Re: [PATCH]PCIE ASPM support - takes 3 |
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On Fri, Jan 18, 2008 at 09:56:28AM +0800, Shaohua Li wrote: > v3->v2, fixed the issues Matthew Wilcox raised. > > 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. > > please review, any comments will be appreciated.
Can you please fix up all of the warnings that checkpatch.pl and sparse produce from this patch?
Also, one small thing:
> --- linux.orig/include/linux/pci.h 2008-01-16 15:59:42.000000000 +0800 > +++ linux/include/linux/pci.h 2008-01-18 09:41:20.000000000 +0800 > @@ -164,6 +164,10 @@ struct pci_dev { > this is D0-D3, D0 being fully functional, > and D3 being off. */ > > +#ifdef CONFIG_PCIEASPM > + void *link_state; /* ASPM link state. */ > +#endif
Can we make this a "real" pointer to a structure? I note that you use two different structures here in this pointer, should you really do that? It's good to get type-checks whereever possible.
thanks,
greg k-h
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