Re: [PATCH] rtlwifi: Fix Kconfig for some corner cases

From: Ben Hutchings <bhutchings@solarflare.com>
To: Larry Finger <Larry.Finger@lwfinger.net>
Cc: <linville@tuxdriver.com>, <linux-wireless@vger.kernel.org>,
	<netdev@vger.kernel.org>, Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [PATCH] rtlwifi: Fix Kconfig for some corner cases
Date: Tue, 9 Jul 2013 01:40:15 +0100	[thread overview]
Message-ID: <1373330415.1860.14.camel@bwh-desktop.uk.level5networks.com> (raw)
In-Reply-To: <51D9AFB2.2030707@lwfinger.net>

On Sun, 2013-07-07 at 13:13 -0500, Larry Finger wrote:
> On 07/07/2013 04:42 AM, Ben Hutchings wrote:
> > On Sat, 2013-07-06 at 21:47 -0500, Larry Finger wrote:
> >>
> >> Although I could not duplicate this result on my machine, it seemed likely
> >> that it was due to the unusual configuration where rtlwifi was being built,
> >> but none of its dependent drivers were selected.
> >
> > I think it just requires:
> >
> > CONFIG_USB=m
> > CONFIG_RTLWIFI=y
> >
> >> The fix is to select rtlwifi only when it is needed.
> >
> > I don't think so.  Consider this configuration:
> >
> > CONFIG_PCI=y
> > CONFIG_USB=m
> > CONFIG_RTL_CARDS=y
> > CONFIG_RTL8192CE=y
> > CONFIG_RTL8192CU=m
> > CONFIG_RTLWIFI=y     # maximum of RTL8192CE=y and RTL8192CU=m
> >
> > The same breakage occurs.
> 
> Ben,
> 
> Thanks for your comments. I certainly do not claim to understand very much about 
> the whole Kbuild process.
> 
> After setting up the above configuration manually, I ran 'make oldconfig' and 
> got back
> 
> CONFIG_RTL_CARDS=m
> CONFIG_RTL8192CE=m
> CONFIG_RTL8192SE=m
> CONFIG_RTL8192DE=m
> CONFIG_RTL8723AE=m
> CONFIG_RTL8188EE=m
> CONFIG_RTL8192CU=m
> CONFIG_RTLWIFI=m
> CONFIG_RTLWIFI_DEBUG=y
> CONFIG_RTL8192C_COMMON=m
> 
> That set of configuration parameters built normally.

But you can still manually set:

CONFIG_PCI=y
CONFIG_USB=m
CONFIG_MAC80211=y   # maybe you had =m here?
CONFIG_RTL_CARDS=y
CONFIG_RTL8192CE=y

and that will select:

CONFIG_RTLWIFI=y

> >> While making this
> >> change, I simplified the configuration so that variable RTLWIFI is never seen
> >> by the user.
> > [...]
> >
> > This will break existing configurations as RTL_CARDS defaults to n.
> 
> I added a 'default y' to the RTL_CARDS stanza. I now get the following:
> 
> finger@larrylap:~/staging> make
> scripts/kconfig/conf --silentoldconfig Kconfig
> *
> * Restart config...
> *
> *
> * Realtek rtlwifi family of devices
> *
> Realtek rtlwifi family of devices (RTL_CARDS) [M/n/?] (NEW)
> 
> That should prevent breakage of existing configurations. It defaults to "m" 
> because mac80211 is built as a module in my configuration.
> 
> > Perhaps you should introduce separate modules for the common PCI and USB
> > support code, similarly to how the rt2x00 modules are organised.
> 
> That would not be very difficult, but it would involve converting the single 
> module rtlwifi into 3 separate entities. Does that make sense to you? I'm not sure.

Yes it does make sense.

Ben.

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