[ 6.607269] ieee80211 phy0: Selected rate control algorithm 'iwl-3945-rs'
[ 6.785512] platform radeon_cp.0: firmware: agent aborted loading radeon/R520_cp.bin (not found?)
[ 6.785688] [drm:r100_cp_init] *ERROR* Failed to load firmware!
[ 6.785761] radeon 0000:01:00.0: failed initializing CP (-2).
[ 6.785829] radeon 0000:01:00.0: Disabling GPU acceleration
[ 6.785891] [drm] radeon: cp finalized
[ 6.785920] radeon 0000:01:00.0: f7151000 unpin not necessary
[ 6.786496] radeon 0000:01:00.0: f7151e00 unpin not necessary
[ 6.786971] [drm] Radeon Display Connectors
[ 6.786974] [drm] Connector 0:
[ 6.786976] [drm] VGA
[ 6.786979] [drm] DDC: 0x7e40 0x7e40 0x7e44 0x7e44 0x7e48 0x7e48 0x7e4c 0x7e4c
[ 6.786982] [drm] Encoders:
[ 6.786984] [drm] CRT1: INTERNAL_KLDSCP_DAC1
[ 6.786987] [drm] Connector 1:
[ 6.786989] [drm] LVDS
[ 6.786992] [drm] DDC: 0xc54 0xc54 0xc58 0xc58 0xc5c 0xc5c 0xc60 0xc60
[ 6.786994] [drm] Encoders:
[ 6.786996] [drm] LCD1: INTERNAL_LVTM1
[ 6.786998] [drm] Connector 2:
[ 6.787000] [drm] S-video
[ 6.787002] [drm] Encoders:
[ 6.787004] [drm] TV1: INTERNAL_KLDSCP_DAC2
[ 6.787006] [drm] Connector 3:
[ 6.787008] [drm] DVI-I
[ 6.787010] [drm] HPD1
[ 6.787013] [drm] DDC: 0x7e50 0x7e50 0x7e54 0x7e54 0x7e58 0x7e58 0x7e5c 0x7e5c
[ 6.787016] [drm] Encoders:
[ 6.787018] [drm] DFP1: INTERNAL_KLDSCP_TMDS1
[ 6.787043] [drm] radeon: power management initialized
[ 6.942496] snd_hda_intel 0000:00:1b.0: irq 46 for MSI/MSI-X
[ 6.942535] snd_hda_intel 0000:00:1b.0: setting latency timer to 64
[ 6.986976] cfg80211: World regulatory domain updated:
[ 6.986980] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[ 6.986985] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[ 6.986989] cfg80211: (2457000 KHz - 2482000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[ 6.986993] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[ 6.986997] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[ 6.987000] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[ 7.161224] [drm] fb mappable at 0xC0040000
[ 7.161227] [drm] vram apper at 0xC0000000
[ 7.161230] [drm] size 4096000
[ 7.161232] [drm] fb depth is 24
[ 7.161234] [drm] pitch is 5120
[ 7.161355] fbcon: radeondrmfb (fb0) is primary device
[ 7.342870] psmouse serio4: synaptics: Touchpad model: 1, fw: 6.2, id: 0x81a0b1, caps: 0xa04713/0x200000/0x0
[ 7.380775] input: SynPS/2 Synaptics TouchPad as /devices/platform/i8042/serio4/input/input9
[ 7.454668] input: HDA Digital PCBeep as /devices/pci0000:00/0000:00:1b.0/input/input10
[ 7.592553] Console: switching to colour frame buffer device 160x50
[ 7.598246] fb0: radeondrmfb frame buffer device
[ 7.598248] drm: registered panic notifier
[ 7.598257] [drm] Initialized radeon 2.16.0 20080528 for 0000:01:00.0 on minor 0
其中这几句意思是找不到radeon/R520_cp.bin，装载firmware失败、初始化失败、无法开启GPU加速功能
暂时没有查找到radeon/R520_cp.bin属于debian的哪个安装包，通过从AMD官方网站下载ati-driver for linux驱动安装后，问题依旧。
偶然间想起了平时折腾的gentoo系统和其他几个LINUX系统，发现居然gentoo系统的/lib/firmware目录下有这个radeon目录，也刚好有需要的文件：
ls /mnt/sda7f/lib/firmware/radeon/
R100_cp.bin R600_pfp.bin RV610_pfp.bin RV635_pfp.bin RV730_pfp.bin
R200_cp.bin RS600_cp.bin RV620_me.bin RV670_me.bin RV770_me.bin
R300_cp.bin RS690_cp.bin RV620_pfp.bin RV670_pfp.bin RV770_pfp.bin
R420_cp.bin RS780_me.bin RV630_me.bin RV710_me.bin
R520_cp.bin RS780_pfp.bin RV630_pfp.bin RV710_pfp.bin
R600_me.bin RV610_me.bin RV635_me.bin RV730_me.bin
于是将gentoo系统下/lib/firmware/radeon目录拷贝到debian系统下/lib/firmware下，重新启动debian系统，恢复正常：
[ 7.020324] ieee80211 phy0: Selected rate control algorithm 'iwl-3945-rs'
[ 7.145568] input: HDA Digital PCBeep as /devices/pci0000:00/0000:00:1b.0/input/input10
[ 7.283375] [drm] radeon kernel modesetting enabled.
[ 7.283739] radeon 0000:01:00.0: setting latency timer to 64
[ 7.283754] [drm] initializing kernel modesetting (RV515 0x1002:0x718A 0x1043:0x1449).
[ 7.283786] [drm] register mmio base: 0xFEFF0000
[ 7.283789] [drm] register mmio size: 65536
[ 7.284112] ATOM BIOS: Asus
[ 7.284134] [drm] Generation 2 PCI interface, using max accessible memory
[ 7.284141] radeon 0000:01:00.0: VRAM: 256M 0x0000000000000000 - 0x000000000FFFFFFF (128M used)
[ 7.284146] radeon 0000:01:00.0: GTT: 512M 0x0000000010000000 - 0x000000002FFFFFFF
[ 7.284166] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
[ 7.284169] [drm] Driver supports precise vblank timestamp query.
[ 7.284199] [drm] radeon: irq initialized.
[ 7.285452] [drm] Detected VRAM RAM=256M, BAR=256M
[ 7.285456] [drm] RAM width 64bits DDR
[ 7.285563] [TTM] Zone kernel: Available graphics memory: 440778 kiB
[ 7.285567] [TTM] Zone highmem: Available graphics memory: 1492270 kiB
[ 7.285570] [TTM] Initializing pool allocator
[ 7.285577] [TTM] Initializing DMA pool allocator
[ 7.285611] [drm] radeon: 128M of VRAM memory ready
[ 7.285614] [drm] radeon: 512M of GTT memory ready.
[ 7.285641] [drm] GART: num cpu pages 131072, num gpu pages 131072
[ 7.286459] [drm] radeon: ib pool ready.
[ 7.287541] [drm] radeon: 1 quad pipes, 1 z pipes initialized.
[ 7.289215] [drm] PCIE GART of 512M enabled (table at 0x0000000000040000).
[ 7.289239] radeon 0000:01:00.0: WB enabled
[ 7.289244] [drm] fence driver on ring 0 use gpu addr 0x10000000 and cpu addr 0xffb59000
[ 7.289321] [drm] Loading R500 Microcode
[ 7.545978] platform radeon_cp.0: firmware: agent loaded radeon/R520_cp.bin into memory
[ 7.546318] [drm] radeon: ring at 0x0000000010001000
[ 7.546355] [drm] ring test succeeded in 8 usecs
[ 7.546617] [drm] ib test succeeded in 0 usecs
[ 7.547297] [drm] Radeon Display Connectors
[ 7.547302] [drm] Connector 0:
[ 7.547305] [drm] VGA
[ 7.547310] [drm] DDC: 0x7e40 0x7e40 0x7e44 0x7e44 0x7e48 0x7e48 0x7e4c 0x7e4c
[ 7.547314] [drm] Encoders:
[ 7.547317] [drm] CRT1: INTERNAL_KLDSCP_DAC1
[ 7.547321] [drm] Connector 1:
[ 7.547323] [drm] LVDS
[ 7.547328] [drm] DDC: 0xc54 0xc54 0xc58 0xc58 0xc5c 0xc5c 0xc60 0xc60
[ 7.547332] [drm] Encoders:
[ 7.547335] [drm] LCD1: INTERNAL_LVTM1
[ 7.547338] [drm] Connector 2:
[ 7.547341] [drm] S-video
[ 7.547344] [drm] Encoders:
[ 7.547347] [drm] TV1: INTERNAL_KLDSCP_DAC2
[ 7.547351] [drm] Connector 3:
[ 7.547354] [drm] DVI-I
[ 7.547356] [drm] HPD1
[ 7.547361] [drm] DDC: 0x7e50 0x7e50 0x7e54 0x7e54 0x7e58 0x7e58 0x7e5c 0x7e5c
[ 7.547365] [drm] Encoders:
[ 7.547368] [drm] DFP1: INTERNAL_KLDSCP_TMDS1
[ 7.547401] [drm] radeon: power management initialized
[ 7.651031] cfg80211: World regulatory domain updated:
[ 7.651037] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[ 7.651044] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[ 7.651050] cfg80211: (2457000 KHz - 2482000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[ 7.651057] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[ 7.651063] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[ 7.651068] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[ 7.920936] [drm] fb mappable at 0xC00C0000
[ 7.920941] [drm] vram apper at 0xC0000000
[ 7.920945] [drm] size 4096000
[ 7.920948] [drm] fb depth is 24
[ 7.920951] [drm] pitch is 5120
[ 7.921107] fbcon: radeondrmfb (fb0) is primary device
[ 8.352727] Console: switching to colour frame buffer device 160x50
[ 8.358438] fb0: radeondrmfb frame buffer device
[ 8.358441] drm: registered panic notifier
[ 8.358449] [drm] Initialized radeon 2.16.0 20080528 for 0000:01:00.0 on minor 0