With Kernel 3.19 HDMI audio works ok with Radeon HD 6670 but not Radeon HD 7750 on Acube Sam460ex AMCC powerpc 460ex board.Also a problem with direct firmware loading or the radeon firmware which loads ok for the Radeon HD 6670 .
[ 2.561952] Linux agpgart interface v0.103 [ 2.566290] [drm] Initialized drm 1.1.0 20060810 [ 2.571164] [drm] radeon kernel modesetting enabled. [ 2.577230] [drm] initializing kernel modesetting (VERDE 0x1002:0x683F 0x1545:0x7750). [ 2.585379] [drm] register mmio base: 0xe90000000 [ 2.590143] [drm] register mmio size: 262144 [ 2.925520] ATOM BIOS: C44501 [ 2.928803] radeon 0001:81:00.0: VRAM: 1024M 0x0000000000000000 - 0x000000003FFFFFFF (1024M used) [ 2.937725] radeon 0001:81:00.0: GTT: 1024M 0x0000000040000000 - 0x000000007FFFFFFF [ 2.945401] [drm] Detected VRAM RAM=1024M, BAR=256M [ 2.950294] [drm] RAM width 128bits DDR [ 2.954331] [TTM] Zone kernel: Available graphics memory: 379212 kiB [ 2.960822] [TTM] Zone highmem: Available graphics memory: 1034572 kiB [ 2.967373] [TTM] Initializing pool allocator [ 2.971766] [TTM] Initializing DMA pool allocator [ 2.976604] [drm] radeon: 1024M of VRAM memory ready [ 2.981610] [drm] radeon: 1024M of GTT memory ready. [ 2.986651] [drm] Loading verde Microcode [ 2.990757] radeon 0001:81:00.0: Direct firmware load for radeon/verde_pfp.bin failed with error -2 [ 2.999908] radeon 0001:81:00.0: Direct firmware load for radeon/verde_me.bin failed with error -2 [ 3.008995] radeon 0001:81:00.0: Direct firmware load for radeon/verde_ce.bin failed with error -2 [ 3.018041] radeon 0001:81:00.0: Direct firmware load for radeon/verde_rlc.bin failed with error -2 [ 3.027184] radeon 0001:81:00.0: Direct firmware load for radeon/verde_mc.bin failed with error -2 [ 3.036203] [drm] radeon/VERDE_mc2.bin: 31500 bytes [ 3.041171] radeon 0001:81:00.0: Direct firmware load for radeon/verde_smc.bin failed with error -2 [ 3.050278] [drm] Internal thermal controller with fan control [ 3.056448] [drm] probing gen 2 caps for device aaa1:bed1 = 18cc41/0 [ 3.110566] [drm] radeon: dpm initialized [ 3.114788] [drm] GART: num cpu pages 262144, num gpu pages 262144 [ 3.126445] [drm] probing gen 2 caps for device aaa1:bed1 = 18cc41/0 [ 3.171357] [drm] PCIE GART of 1024M enabled (table at 0x0000000000277000). [ 3.178681] radeon 0001:81:00.0: WB enabled [ 3.182925] radeon 0001:81:00.0: fence driver on ring 0 use gpu addr 0x0000000040000c00 and cpu addr 0xffc01c00 [ 3.193045] radeon 0001:81:00.0: fence driver on ring 1 use gpu addr 0x0000000040000c04 and cpu addr 0xffc01c04 [ 3.203167] radeon 0001:81:00.0: fence driver on ring 2 use gpu addr 0x0000000040000c08 and cpu addr 0xffc01c08 [ 3.213287] radeon 0001:81:00.0: fence driver on ring 3 use gpu addr 0x0000000040000c0c and cpu addr 0xffc01c0c [ 3.223409] radeon 0001:81:00.0: fence driver on ring 4 use gpu addr 0x0000000040000c10 and cpu addr 0xffc01c10 [ 3.255059] radeon 0001:81:00.0: fence driver on ring 5 use gpu addr 0x0000000000075a18 and cpu addr 0xf90b5a18 [ 3.265199] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 3.271837] [drm] Driver supports precise vblank timestamp query. [ 3.277957] radeon 0001:81:00.0: radeon: MSI limited to 32-bit [ 3.283833] ppc4xx_setup_msi_irqs: fail allocating msi interrupt [ 3.289927] [drm] radeon: irq initialized. [ 4.047989] [drm:r600_ring_test] *ERROR* radeon: ring 0 test failed (scratch(0x850C)=0xCAFEDEAD) [ 4.056845] radeon 0001:81:00.0: disabling GPU acceleration [ 4.261053] [drm] Radeon Display Connectors [ 4.265626] [drm] Connector 0: [ 4.268744] [drm] HDMI-A-1 [ 4.271735] [drm] HPD4 [ 4.274313] [drm] DDC: 0x6570 0x6570 0x6574 0x6574 0x6578 0x6578 0x657c 0x657c [ 4.281755] [drm] Encoders: [ 4.284768] [drm] DFP1: INTERNAL_UNIPHY2 [ 4.289060] [drm] Connector 1: [ 4.292125] [drm] DVI-I-1 [ 4.294929] [drm] HPD2 [ 4.297476] [drm] DDC: 0x6560 0x6560 0x6564 0x6564 0x6568 0x6568 0x656c 0x656c [ 4.304894] [drm] Encoders: [ 4.307872] [drm] DFP2: INTERNAL_UNIPHY [ 4.312064] [drm] CRT1: INTERNAL_KLDSCP_DAC1 [ 4.465445] [drm] fb mappable at 0x80478000 [ 4.469662] [drm] vram apper at 0x80000000 [ 4.473775] [drm] size 8294400 [ 4.476840] [drm] fb depth is 24 [ 4.480084] [drm] pitch is 7680 [ 4.759376] Console: switching to colour frame buffer device 240x67 [ 4.838736] radeon 0001:81:00.0: fb0: radeondrmfb frame buffer device [ 4.845560] radeon 0001:81:00.0: registered panic notifier [ 4.856007] [drm] Initialized radeon 2.40.0 20080528 for 0001:81:00.0 on minor 0
[ 31.335598] [drm:dce6_audio_get_pin] *ERROR* No connected audio pins found!