On Mon, Jul 26, 2010 at 2:14 PM, Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote: > On Mon, Jul 26, 2010 at 02:06:51PM -0700, Luis R. Rodriguez wrote: > >> No, ASPM must be enabled by the Systems Integrator through the BIOS, there are >> other settings that have to be taken care of like modifying some PCI entrance and >> exit latency timers, the number of FTS packets we send to exit L0s, amongst >> other things. If a user selectively enables L1 but the BIOS had it disabled on >> the device it may not work correctly. > > That's really the job of the driver. The problem is that sometimes tweaks need to be done on the PCI controller/root complex, not the PCIE device/endpoint. Today these sort of changes *are* handled by the respective systems integrator/BIOS team and varies depending on the root complex used. Atheros does not handle these at all in the driver. > If the ASPM policy is set to > powersave, the fadt doesn't indicate that ASPM should be disabled and > the bus's _OSC method grants full control then the kernel will enable > whatever combination of L states meet the latency constraints. If the > hardware has additional constraints then the hardware-specific driver > needs to handle them. This makes sense but Is there an API for this? > We don't rely on the BIOS to set up ASPM states. Nor does Windows. Understood, but today some tweaks seem to be done on the BIOS depending on the endpoint / root complex. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
