On Wed, Jun 11, 2008 at 08:48:58PM -0700, Jack Vogel wrote: > On Wed, Jun 11, 2008 at 7:16 PM, Sam Leffler <[EMAIL PROTECTED]> wrote: > > [trimming cc list to reduce spamage] > > > > Pyun YongHyeon wrote: > >> > >> On Wed, Jun 11, 2008 at 09:52:23AM -0700, Jack Vogel wrote: > >> > On Wed, Jun 11, 2008 at 12:33 AM, Pyun YongHyeon <[EMAIL PROTECTED]> > >> wrote: > >> > > On Tue, Jun 10, 2008 at 09:51:53AM -0700, Jack Vogel wrote: > >> > > > This is a small patch that Sam came up with for me, it will allow > >> > > > drivers to know > >> > > > when a vlan attaches. > >> > > > > >> > > > It is transparent to any code that doesn't want to change, but > >> this > >> > > > will allow my > >> > > > drivers to finally utilize the vlan hardware filter (something > >> Linux has had for > >> > > > ever but we lacked). > >> > > > > >> > > > >> > > Just curious, is there any rule how to use that new capability? > >> > > Because drivers will receive events whenever VLAN tags are > >> > > added/removed they would know how to act for these events. If > >> > > promiscuous mode is on for interface, driver should not filter any > >> > > VLAN tagged frames, right? > >> > > If users want to disable VLAN hardware filtering feature what is > >> > > best way to perform this? Introducing a new flag like > >> > > IFCAP_VLAN_HWFILT or add a new sysctl that control this feature? > >> > > I guess VIA Rhine III also have VLAN hardware filtering capability > >> > > so it would be even better if we have a way to share common part. > >> > > All the patch does is have the vlan driver generate events when it > >> attaches > >> > or detaches from a NIC, there are no rules, however I can tell you what > >> > I'm coding into this in the Intel drivers. > >> > > The way it works is the driver registers a callback for each event, > >> I will > >> > call that [igb,em,ixgbe]_register_vlan(), and unregister obviously. > >> > > Right now, the drivers just generically enable VLAN capability > >> because > >> > there is never a trigger to know IF and WHEN you need to do so, but > >> > with this change the VLAN capability will only get turned on by the > >> > registration routine. > >> > > Most significantly, now when the pseudo device it gives the driver > >> > the VLAN tag, this will mean the driver will be able from the start > >> > to use the VFTA, the hardware filter, for each vlan attach the driver > >> > will add the ID into this table. > >> > > The unregister event will turn the table entry off, and if this is > >> the > >> > last VLAN being detached it will then disable the features. > >> > > Oh yes, these routines will also take care of the size change of > >> > the frame due to the tag. I already have the changes in place in > >> > the igb drive, and they are working great. > >> > > I do not understand why you think you need a flag to disable this, > >> > yes it could be done, but why? If you need to do some sort of > >> > debugging won't a system not using vlans and in promiscuous > >> > mode do just fine? > >> > > >> I guess this would be the same reason why FreeBSD have a way to > >> disable checksum offload for buggy hardware. Diabling all hardware > >> VLAN assistance due to broken VLAN filtering doesn't look right. > >> > >> > It just seems to violate the whole reason for doing vlans in the > >> > first place, however perhaps I am missing something? I do not > >> > believe the Linux driver has some way to disable use of the table > >> > but I'll double check on that. > >> > > Remember, this change requires NO driver changes unless they > >> > wish to take advantage of the ability. > >> > >> Yes. > >> > >> > > Cheers, > >> > > Jack > >> > >> Thanks. > > > > Sounds like there needs to be a h/w vlan assist capability bit that > > controls > > this in the driver. Then you'd have a way to disable via ifconfig w/ a > > trivial mod. > > I don't want to create stuff in ifconfig when I'm not convinced > of the need. If there were, as he says, 'buggy hardware', specifically > buggy Intel hardware, then either our drivers would have had special > errata or workarounds in it for that, but none of the OS drivers have > any special code for issues involving VFTA (the filter) or other VLAN > controlling components that I am aware of. > > If there are other network drivers that are buggy in this regard then why > encumber the generic interface due to that, let the drivers deal with it, > via sysctl or something of the sort. > > There are enough real cases of hardware problems we need to address in > code that I don't just want to modify code on the mere theoretical > possibility > of such. > > How bout this, we put the change into HEAD, I add support as I've planned > into > the em and igb drivers, and then we let them get tested, if a real problem > comes > up, THEN we worry about adding special case code, how's that? >
Please go ahead. I don't have any objections on it. I just thought it would be better to show a flag to indicate hardware VLAN filtering is active in ifconfig(8) and have user disable this feature in some rare cases. > Regards, > > Jack -- Regards, Pyun YongHyeon _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
