RADEON(0): [drm] Failed to open DRM device: No such file or directory error

[StompDagger1@yahoo.com]

greetings,

since I've updated my kernel to 3.13.x I'm unable to start X on my radeon cards.

the setup works great in kernel 3.12.8, here is part of Xorg log for that adaper:
[    51.782] (II) [KMS] Kernel modesetting enabled.
[    51.782] (II) RADEON(0): RADEONPreInit_KMS
[    51.782] (II) RADEON(0): Creating default Display subsection in Screen section
        "Default Screen Section" for depth/fbbpp 24/32
[    51.782] (==) RADEON(0): Depth 24, (--) framebuffer bpp 32
[    51.782] (II) RADEON(0): Pixel depth = 24 bits stored in 4 bytes (32 bpp pixmaps)
[    51.782] (==) RADEON(0): Default visual is TrueColor
[    51.782] (==) RADEON(0): RGB weight 888
[    51.782] (II) RADEON(0): Using 8 bits per RGB (8 bit DAC)
[    51.782] (--) RADEON(0): Chipset: "ATI Radeon HD 3600 XT" (ChipID = 0x9598)
[    51.829] (EE) RADEON(0): [drm] Failed to open DRM device for pci:0000:06:00.0: No such file or directory
[    51.829] (EE) RADEON(0): Kernel modesetting setup failed
[    51.829] (II) RADEON(0): RADEONFreeScreen
[    51.829] (II) UnloadModule: "radeon"
[    51.829] (EE) Screen(s) found, but none have a usable configuration.
[    51.829] (EE) 
Fatal server error:
[    51.829] (EE) no screens found(EE) 
[    51.829] (EE) 
Please consult the The X.Org Foundation support 
         at http://wiki.x.org

is that a X bug? what is the right place to debug it, X or xf86-video-ati?

Thanks.
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