Date: Thu, 19 Feb 2009 19:24:07 +0900 From: Hiroharu Tamaru <tamaru@myn.rcast.u-tokyo.ac.jp> To: freebsd-net@freebsd.org Subject: Can ASPM be disabled on 82573 to allow Jumbo Frames with em(4)? Message-ID: <sa6bpsyk9mg.wl%tamaru@myn.rcast.u-tokyo.ac.jp>
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Hi I am not sure if I am understanding things right, but is it possible to forcibly disable ASPM in em(4) for 82573 devices? What I wanted to do is to use Jumbo Frames for these NICs and I saw in sys/dev/e1000/if_em.c that says: | static int | em_ioctl(struct ifnet *ifp, u_long command, caddr_t data) | { (snip) | case SIOCSIFMTU: (snip) | case e1000_82573: | /* | * 82573 only supports jumbo frames | * if ASPM is disabled. | */ | e1000_read_nvm(&adapter->hw, | NVM_INIT_3GIO_3, 1, &eeprom_data); | if (eeprom_data & NVM_WORD1A_ASPM_MASK) { | max_frame_size = ETHER_MAX_LEN; | break; | } | /* Allow Jumbo frames - fall thru */ | case e1000_82571: I also found that in Linux, they seem to disable ASPM for certain cases: http://kerneltrap.org/mailarchive/linux-netdev/2007/10/31/374573 So I started to wonder if there is a knob already in FreeBSD to disable ASPM for 82573 and (as a side effect?) allows one to use Jumbo Frames with this device, or I such can be introduced easily. It would be nice to be able to enable Jumbo Frames if the power consumption is not of a problem.. Thanks. Hiroharu
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