On Sun, Jun 20, 2010 at 4:18 AM, Maxim Levitsky <maximlevitsky@xxxxxxxxx> wrote: > On Sun, 2010-06-20 at 01:13 -0700, Luis R. Rodriguez wrote: >> > commit ac5de416f822917b927958b21186a82141550da7 >> > Author: Maxim Levitsky <maximlevitsky@xxxxxxxxx> >> > Date: Thu Jun 17 23:21:42 2010 +0300 >> > >> > ath5k: disable ASPM >> >> You are not disabling ASPM, you are disabling L0s. ASPM can work with >> L1, for example. > This is left over from original patch. Your latest patch still has all this old info, please adjust. > with open coded code I was able to disable just L0s and get stable > operation. > Note however that with this patch which implies CONFIG_PCIEASPM, pci > core disables both L0s and L1 You do not need CONFIG_PCIEASPM to use ASPM on Linux, that is another thing I have been meaning to clarify upstream but haven't had time to do so yet. > (I still need to test and see if I need that patch at all. Maybe just > enabling CONFIG_PCIEASPM is enough...) You should be able to test ASPM by just enabling the driver. >> > Atheros card on Acer Aspire One (AOA150, Atheros Communications Inc. AR5001 >> > Wireless Network Adapter [168c:001c] (rev 01)) doesn't work well with ASPM >> > enabled. With ASPM ath5k will eventually stall on heavy traffic with often >> > 'unsupported jumbo' warnings appearing. Disabling ASPM L0s in ath5k fixes >> > these problems. >> > >> > Reproduced with pcie_aspm=force and by using 'nc < /dev/zero > /dev/null' at >> > both ends (usually stalls within seconds). >> >> I *highly* discourage the use of pcie_aspm=force, in fact I'm inclined >> to just remove this junk code from the kernel. What you should do to >> test ASPM on a device is to use setpci on the config space. I have >> documented how you can do this here: >> >> http://wireless.kernel.org/en/users/Documentation/ASPM >> >> Reason for discouraging this is when you use this you enable ASPM on >> *all* root complexes and *all* devices which do support ASPM. If you >> have another device which is capable of ASPM but has it disabled for >> some reason you will run into other issues. >> >> I should also note that loading a module already has an effect on >> devices for ASPM. An example today is ath9k's ath9k_hw_init() which >> runs simply during module load, this has some ASPM related code which >> for example disables the PLL for ASPM for AR9003. I don't recall >> exactly what we do with ath5k but just giving you an idea. To truly >> test ASPM well I recommend to do something similar as with this script >> or you can just give it a shot. >> >> http://kernel.org/pub/linux/kernel/people/mcgrof/aspm/enable-aspm >> >> Not like I expect very different results but just wanted to clarify >> the details on force aspm. >> >> Why are you disabling L0s for all devices though? Why not just for the >> reported device? Granted, L0s won't save you much more power but >> still, why remove it completely, your commit log does not address that >> in any way. It only states you have issues with L0s on one chipset but >> what the patch really implies is you are disabling L0s completely for >> all ath5k chipsets. > > First of all there aren't many PCIE ath5k based devices. Doesn't matter. > Two of them are known to be broken. Which ones? > Also Jussi Kivilinna said that he found that in windows .inf file there > are some instructions to enable L1 but not L0s. For which chipsets? > Note that I tested that again, and card works very stable. Thanks for your work on this, I want to just check internally if there is another way, that's all. > I didn't see a single drop to 0 bytes/s. In fact throughput never drops > below 1 Mb/s. (usually about 2.4 Mb/s, with rare drops for few seconds > to ~1Mb/s) Disabling L0s should not affect performance. 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
