[CentOS] Headphones volume control not working in CentOS 7

Hi all,

I hope someone could enlighten me...
How could I resolve the fact that the volume controls of all the 
headphones I try on CentOS 7 are not working, they are OK on CentOS 6 
but impossible to make them work on my Thinkpad Laptop with an iPhone 
headphones or a Marshal Monitor plugged with a jack connector...
Those 2 headphones work correctly in CentOS 6...
What could I do to get the same behavior on CentOS 7 and this damned 
Gnome 3 ?
Thanks for your help...

-- 
(°-	
//\     Bernie
v_/_    The Mad Axeman