KMS:RV770PRO:HD4850 1G VRAM performance regression since Fedora 12

[Dennis J.]

Hi,
Since Fedora 12 the radeon driver seems to have trouble working with my 
graphics card (hd4850). It functions correctly but much slower than it does 
under Fedora 11 which I'm still running because of this problem. I've also 
tried F13 and F14alpha RC4 with the same problems.
I filed a bug in Red Hats bugzilla:
https://bugzilla.redhat.com/show_bug.cgi?id=553059

There I've attached two sysprof profiles of a youtube video playing (the 
same one in both cases). One created on F11 with good performance and one 
on F14alpha RC4 with bad performance.

What stands out is that the F14 profile contains an order of magnitude more 
samples than the F11 one and that raw_local_irq_restore shows up 
prominently in the F14 profile but not the F11 one.

Could it be that there is some problem with input processing that kills the 
drivers performance? That is the only thing right now that prevents me from 
moving to a new Fedora release.

I've also got a Laptop with an "ATI Mobility Radeon HD 4670 (ChipID = 
0x9488" with Fedora 13 installed and there I don't see any performance issues.

Regards,
   Dennis