Hi,

What is a convenient way to find the name of the linux
CONFIG_ parameter that needs to be enabled to support a
certain device/feature? Googling is not very helpful
as one usually gets various config file listings. I
have not been able to find much information under the
Documentation directory in the kernel either. Other
avenues like the manufacturer's websites are also not
very helpful.

I support applications that run on linux on various
platforms. It appears that many drivers that used to
be enabled in older kernel versions need to be specifically
enabled through settig some (usually obscure) CONFIG_
parameters when the kernel is upgraded. I have made sure
that when I upgrade, all the parameters that were set
before are set in the new config files. But apparently,
many drivers that used to be enabled by some generic
CONFIG_ parameter now need their on specific sub-parameter.
Things that used to work before stop working on kernel
upgrade even though our applications/platforms may not
have changed.

I feel that there must be a less painful way to figure
this out than the one I seem to be using - usually
hitting my head against a wall .

Thanks.

Lu

Sorry to be the bearer of bad news - try and find a softer wall.
It's just a lot of "leg work" - ploughing through the options. You could (should) check the kernel changelog, but you'll still miss plenty of things, and not even understand plenty of others.
Just the way it is for us poor mortals out in userland.