5c87579e65
Add infrastructure to track "maximum allowable latency" for power saving policies. The reason for adding this infrastructure is that power management in the idle loop needs to make a tradeoff between latency and power savings (deeper power save modes have a longer latency to running code again). The code that today makes this tradeoff just does a rather simple algorithm; however this is not good enough: There are devices and use cases where a lower latency is required than that the higher power saving states provide. An example would be audio playback, but another example is the ipw2100 wireless driver that right now has a very direct and ugly acpi hook to disable some higher power states randomly when it gets certain types of error. The proposed solution is to have an interface where drivers can * announce the maximum latency (in microseconds) that they can deal with * modify this latency * give up their constraint and a function where the code that decides on power saving strategy can query the current global desired maximum. This patch has a user of each side: on the consumer side, ACPI is patched to use this, on the producer side the ipw2100 driver is patched. A generic maximum latency is also registered of 2 timer ticks (more and you lose accurate time tracking after all). While the existing users of the patch are x86 specific, the infrastructure is not. I'd like to ask the arch maintainers of other architectures if the infrastructure is generic enough for their use (assuming the architecture has such a tradeoff as concept at all), and the sound/multimedia driver owners to look at the driver facing API to see if this is something they can use. [akpm@osdl.org: cleanups] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jesse Barnes <jesse.barnes@intel.com> Cc: "Brown, Len" <len.brown@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
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| .. | ||
| bcm43xx | ||
| hostap | ||
| prism54 | ||
| zd1211rw | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| airo.c | ||
| airo.h | ||
| airo_cs.c | ||
| airport.c | ||
| arlan-main.c | ||
| arlan-proc.c | ||
| arlan.h | ||
| atmel.c | ||
| atmel.h | ||
| atmel_cs.c | ||
| atmel_pci.c | ||
| hermes.c | ||
| hermes.h | ||
| hermes_rid.h | ||
| i82586.h | ||
| i82593.h | ||
| ipw2100.c | ||
| ipw2100.h | ||
| ipw2200.c | ||
| ipw2200.h | ||
| netwave_cs.c | ||
| orinoco.c | ||
| orinoco.h | ||
| orinoco_cs.c | ||
| orinoco_nortel.c | ||
| orinoco_pci.c | ||
| orinoco_pci.h | ||
| orinoco_plx.c | ||
| orinoco_tmd.c | ||
| ray_cs.c | ||
| ray_cs.h | ||
| rayctl.h | ||
| spectrum_cs.c | ||
| strip.c | ||
| todo.txt | ||
| wavelan.c | ||
| wavelan.h | ||
| wavelan.p.h | ||
| wavelan_cs.c | ||
| wavelan_cs.h | ||
| wavelan_cs.p.h | ||
| wl3501.h | ||
| wl3501_cs.c | ||
| zd1201.c | ||
| zd1201.h | ||
README
README ------ This directory is mostly for Wireless LAN drivers, in their various incarnations (ISA, PCI, Pcmcia...). This separate directory is needed because a lot of driver work on different bus (typically PCI + Pcmcia) and share 95% of the code. This allow the code and the config options to be in one single place instead of scattered all over the driver tree, which is never 100% satisfactory. Note : if you want more info on the topic of Wireless LANs, you are kindly invited to have a look at the Wireless Howto : http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/ Some Wireless LAN drivers, like orinoco_cs, require the use of Wireless Tools to be configured : http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Tools.html Special notes for distribution maintainers : 1) wvlan_cs will be discontinued soon in favor of orinoco_cs 2) Please add Wireless Tools support in your scripts Have fun... Jean