Configuring flow control for network interfaces

[John Baldwin]

On Tuesday 18 May 2010 1:30:32 pm Pyun YongHyeon wrote:
> On Tue, May 18, 2010 at 01:15:37PM -0400, John Baldwin wrote:
> > I think it would be useful if we could pick a device-independent interface for 
> > configuring flow control on network interfaces, perhaps as media options via 
> > ifconfig.  I know that the msk(4) driver allows RX and TX flow control to be 
> > toggled via the link0 and link1 flags (the manpage for msk(4) needs updating 
> > on this topic I think).  I have a hack for work to disable TX flow control on 
> 
> The hack used in e1000phy(4), brgphy(4) and ip1000phy(4) should be
> removed.

So this looks to actually be different (I was confused).  Apparently the 
link[012] flags are separate from the flag[012] shared flags for ifmedia.
It does look like the link0 use in these drivers could be replaced by proper
use of IFM_ETH_MASTER media option flag instead.  It seems that IFM_ETH_MASTER
is missing from IFM_SUBTYPE_ETHERNET_OPTION_DESCRIPTIONS in ifmedia.h which
would need to be fixed before ifconfig could get/set it.  Once that change is
in place I think these drivers could check that flag instead of the IFF_LINK0
to determine if they are the master.

> > cxgb(4), but it doesn't use flow control currently.  Is flow control ethernet-
> > specific?  If so, perhaps we could add two new flags for RX and TX flow 
> > control to the Ethernet-specific options in that case?  Do folks have other 
> > ideas?
> > 
> 
> AFAIK marius@ is working on it and may have latest patches.

Ok.  Does his patch use Ethernet-specific options or some other approach?

-- 
John Baldwin