Re: [17/26] b43: refuse to load unsupported firmware

[Greg KH]

On Sat, Nov 19, 2011 at 05:22:10PM +0000, Ben Hutchings wrote:
> On Fri, 2011-11-18 at 16:02 -0800, Greg KH wrote:
> > 3.1-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > [This patch is supposed to be applied in 3.1 (and maybe older) branches only.]
> > 
> > New kernels support newer firmware that users may try to incorrectly use
> > with older kernels. Display error and explain the problem in such a case
> > 
> > Signed-off-by: RafaÅ? MiÅ?ecki <zajec5@xxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
> > 
> > ---
> >  drivers/net/wireless/b43/main.c |    7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > --- a/drivers/net/wireless/b43/main.c
> > +++ b/drivers/net/wireless/b43/main.c
> > @@ -2508,6 +2508,13 @@ static int b43_upload_microcode(struct b
> >  		b43_print_fw_helptext(dev->wl, 1);
> >  		err = -EOPNOTSUPP;
> >  		goto error;
> > +	} else if (fwrev >= 598) {
> > +		b43err(dev->wl, "YOUR FIRMWARE IS TOO NEW. Support for "
> > +		       "firmware 598 and up requires kernel 3.2 or newer. You "
> > +		       "have to install older firmware or upgrade kernel.\n");
> > +		b43_print_fw_helptext(dev->wl, 1);
> > +		err = -EOPNOTSUPP;
> > +		goto error;
> [...]
> 
> Again, I strongly object to this way of handling the incompatibility.
> The revision check is fine, but the solution must be to assign a
> different filename for the newer revisions.  The changes to 3.0/3.1
> should be deferred until this is resolved.

You can object, however the driver author and maintainer wants it done
this way for now, so that's a valid solution that I have to accept.  It
solves real bugs that people have already hit when running the 3.0 and
3.1 kernels.  Propagating a userspace tool change for those systems
would be much harder, if not impossible, don't you think?  It would also
require a much more intrusive change to the driver infrastructure to
handle such a proposed change.

thanks,

greg k-h
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