I found something by Googling about roots and negative meaning but more than it I want to know if there is a positive or neutral usage too. Is it something like geek or nerd and the other slangy stereotypes or a serious history is hidden behind ?
The short: yes, there is "history" behind the term similar to the information from the OED via @FumbleFingers. However, many white farmers were and are proud of their hard work ethic and are not ashamed of a farmer's tan.
The degree of pejoration, however, is much more complex, and I'm just baffled at the strong responses that the use of redneck is always negative. The long: a different perspective.
In the last 20+ years of country and country pop music, lyricists have ?reclaimed redneck much like the Black community has re-purposed nigger. The 2004 country hit "Redneck Woman" by Gretchen Wilson exemplifies the "I'm X and proud of it" sentiment, @JonHanna's excellent response.
I'm a redneck woman, I ain't no high class broad / I'm just a product of my raising; I say "hey y'all" and "yee-haw" / And I keep my Christmas lights out on my front porch all year long / And I know all the words to every Charlie Daniels* song / So here's to all my sisters out there keeping it country / Let me get a big "hell yeah" from the redneck girls like me
*In subsequent refrains, she names Tanya Tucker and ol' Bocephus
Her bio includes a National Coalition for Literacy Leadership Award in 2009, the same year she launched her own record label, "Redneck Records."
Similar examples of redneck ?pride can be heard in the following examples, which is by no means a comprehensive list:
- Hi-tech Redneck by George Jones
- Redneck Rhythm & Blues by Brooks &Dunn
- Redneckified by Neal McCoy
- Hicktown by Jason Aldean
- A few more Rednecks by Charlie Daniels Band
- Chicken Fried by Zac Brown Band
- Hillbilly Deluxe by Brooks & Dunn
- Redneck Yacht Club by Craig Morgan
- That's how they Do it In Dixie by Hank Williams Jr.
- Boondocks by Little Big Town
- Country Boy by Alan Jackson
n.b.: The main point expressed in most of these songs is not self-denigrating humor à la Jeff Foxworthy or Chris Rock. Country music more often expresses praise and positive identification with its heritage.
Personally, I'm a Virginia native, and while it's more likely you'd call me a nerd than a redneck, I would not be offended by either. In my experience, Southerners are perfectly likely to identify themselves with the term.
One of my favorite country songs is Sammy Kershaw's Queen of my Double Wide Trailer, with this refrain:
So I made her the queen of my double wide trailer / With the polyester curtains and the redwood deck / Now she's run off and I've got to tail her / Dang her black heart and her pretty red neck
Definitely an example of a red neck being a desirable quality.
I know of a context in which "wife-swapping sodomite" had positive connotations: someone had referred to her political opponents as "a bunch of wife-swappers and sodomites", and some of said opponents made a humorous attack on her out of referring to themselves as "wife-swapping sodomites".
Any negative term can be re-purposed.
While some might argue Lenny Bruce came close, generally they cannot be re-purposed by people outside of the group they describe. The re-purposing often requires humour and while that can be light-hearted, often it's with a certain grim irony that doesn't lose sight of the negative sense. While a few can make complete reversals, they have generally already lost some of the negativity already (gay could probably not have become the neutral term it was if many people realised that it was applied to homosexuals because it once had meanings of "prostitute" and "promiscuous").
You can normally find a bunch of positive uses for just about any term by googling for "X and proud of it" or "I'm an X and proud of it", but to understand such positive senses you have to acquaint yourself more with the demographic and culture it covers than you do with uses of the term generally.
Arguably this is General Reference, but the OED entry for slang redneck (orig. N. Amer.) is...
Originally: a poorly educated white person working as an agricultural labourer or from a rural area in the southern United States, typically considered as holding bigoted or reactionary attitudes.
Now also more generally: any unsophisticated or poorly educated person, esp. one holding bigoted or reactionary attitudes.
Obviously the white farm labourer would get a red sunburnt neck that wouldn't be noticeable on black workers (also negatively stereotyped at the time). And opinionated reactionaries, etc. can get quite worked up about innovation and change, becoming red in the face and neck when venting their spleen.
I've used and heard redneck many thousands of times, but never once positively. Always negative.
Sometimes people can playfully refer to themselves as "rednecks", but almost always the term is considered a derogatory one and synonymous with "white trash," "bigotry," or overly "provincial" folks. In the U.S. rednecks are thought to come from small farming communities, especially in the south, or blue collar towns. They, however, equally reside in the large cities. Recently, cable TV has begun to glorify the redneck.