Re: [PATCH] ixgb: Convert to new vlan model.

[Ben Hutchings <bhutchings@solarflare.com>]

On Tue, 2010-12-14 at 13:29 -0800, Jesse Gross wrote:
> On Tue, Dec 14, 2010 at 11:15 AM, Ben Hutchings
> <bhutchings@solarflare.com> wrote:
> > On Tue, 2010-12-14 at 12:08 -0700, Tantilov, Emil S wrote:
> >> Ben Hutchings wrote:
> >> > On Tue, 2010-12-14 at 11:09 -0700, Tantilov, Emil S wrote:
> >> >> Ben Hutchings wrote:
> >> >>> On Mon, 2010-12-13 at 19:42 -0800, Jesse Gross wrote:
[...]
> >> >>> I think this should reject attempts to change just one flag with
> >> >>> -EINVAL, rather than quietly 'fixing' the setting.
[...]
> Ben, I agree that limiting the settings to what is actually supported
> is conceptually cleaner but in practice it's not very intuitive.  If
> you try to turn something off and the response is that it's invalid,
> most people are going to assume that you just can't do it.  This is
> especially true since you actually can't turn these settings off in
> most drivers.
> 
> There's a precedent for this type of thing: turn off TX checksum
> offloading and watch scatter/gather and TSO be automatically disabled
> as well.  It makes sense - the user requested a change, we do what is
> necessary to make that happen without requiring them to understand why
> these features are interrelated.

That reflects a general dependency and not a driver- or hardware-
specific restriction.  But I see your point.

Perhaps the ethtool utility should check the result after applying
offload changes and report any additional automatic changes.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.