Hello friends.. i want to thank you for your help..some of my problems have been solved but some still persists.
The Wifi and Screen brightness control problem have been by installing backport kernel and firmware.
However I still have sound problem..
I have found 2 devices on alsamixer namely:
0 [HDMI ]: HDA-Intel - HDA Intel HDMI HDA Intel HDMI at 0xe3610000 irq 64
1 [PCH ]: HDA-Intel - HDA Intel PCH HDA Intel PCH at 0xe3614000 irq 62