Radeon HD 7500M/7600M [Thames] and Intel HD duo

[Mitt Green <mitt_green@yahoo.com>]

Hi everyone,

I am having a trouble with Radeon support. I am using a custom 3.18.20 kernel
(with everything unnecessary - and, as far as I see, something necessary - removed).

I can't play 4k videos (sometimes even fullhd) smoothly, CPU goes up to 100%
and remains there until the video is stopped. With hd (720p) CPU usage is about 70%.

As for more complete hardware configuration, I have Core i5, dual-core with four
threads, integrated Intel HD (4000 I believe), AMD Radeon Thames [7500M/7600M].

Previously I wasn't using AMD/ATI setting in kernel config, nor GPU switching,
I feel that Intel GPU is fairly well alone, unless you want to do something heavier
like those 4k videos.

I tried some LiveCDs just to make sure that the problem is in system config,
not from the hardware side which isn't that weak; I was able to decode those
UltraHD mp4s.

I've tried enabling ATI Radeon, installing firmware-amd-graphics (by the
way the only thing I need from there is TURKS_pfp.bin), putting these things
together, result is the same as with Intel HD solo, except for higher RAM
consumption.

Here's the paste of my current Intel-only config: 
http://paste.lisp.org/display/158650

Any help will be highly appreciated.

Thanks and have a good day,

                                    Mitt