On Tuesday, February 17, 2015 at 6:56:13 PM UTC+1, Manuel Braga wrote: > On Tue, 17 Feb 2015 12:00:27 +0200 Simos Xenitellis > > > > At http://www.phoronix.com/scan.php?page=news_item&px=MTg4Mjg it > > mentions that Intel is doing Linux work on the PowerVR VXD392 VPU (as > > is used on Baytrail). > > Is the VPU similar to what exists on the A80? > > What is a VPU?, wikipedia says that a VPU is another term for GPU. > And at the end this is huge confusion, that make people believe that for > have hardware accelerated video playback is a requirement to have and > use the GPU.
CPU : Central Processing Unit GPU : Graphics Processing Unit VPU : Video Processing unit GPU, VPU are specialized processing unit/cores for specific workloads to unload the CPU or gain performance which is out of reach for a general purpose PU GPGPU: General purpose GPU. -> OpeCL etc. Not that confusing IMHO, A little archaic perhaps. > > This is wrong, it come from the fact that in the PC(x86) world are used > graphic cards that are actually are (gpu + display engine + video codec > engine), so this is 3 kind of difference hardware types put together in > this some called graphic card. > As this graphic card is one identity, it is usually all handled by the > same software driver. In x86 land we started with CGA, EGA and VGA cards. Which were a little more than "Diplay Controllers". And were called "video cards" which was used pre x68. Because the C64 etc used a "composite video signal" to interface with tv's/display's Than came the "graphics accelerators", which would offload graphics processing from the CPU and send results back to CPU or directly to the display controller. http://commons.wikimedia.org/wiki/File:VideoLogic_Apocalypse_3Dx.jpg#mediaviewer/File:VideoLogic_Apocalypse_3Dx.jpg An ancient PowerVR GPU for x86 without the display controller. Because the chain CPU->GPU/Display Controller->Display. The display controller became embedded to the GPU cards. Apart from that the came MPEG cards wich would decode MPEG video and 'stream' the result back to the system. Because video decoding, VPU, should at the same place as the GPU the chain is broken. CPU -> VPU -> CPU -> GPU -> Display Thus most GPU cards now have a video decoder onboard as well. CPU -> VPU/GPU/Display Controller -> Display > > In ARM case this is not the case, > http://www.cnx-software.com/2013/12/10/most-embedded-gpus-do-not-support-hardware-video-decoding-acceleration-the-vpu-does/ The driver issue is more a "Mix and Match" issue. In x86 the GPU/VPU/Display Controller are usually on one device. The set is alway the same and using a single driver makes sense. In ARM land the CPU,GPU,VPU,Display Controller are mixed and matched on a single device. Thus a single driver does not make sense. Hence the need for seperate drives and some glue (DeviceTree). Also the parts are no longer aligned but are placed side by side on the same memory(bus). Luc has mostly figured out the Mali GPU and is now working on the display controller. For A312 and A80 they chose Imagination's PowerVR as the GPU, I don't know if they chose the use Imagination parts for the Display Controller and VPU > > Please lets use a more correct term, that creates no ambiguity of what > we are speaking about. > > Video Codec Engine, is the correct name for this type hardware in the > sunxi(allwinner) case. This is the hardware to use for decoding and > encoding of video codecs. codec comes from coding and decoding. The VPU does more: ColorCode conversion Scaling etc. So calling it a mere codec is not more accurate. "Media Processing Unit" I think is better. It whould also cover the audio codec and remove the confusion with "video cards" But the Market/Marketing is stuck on the "video" term. > > And in sunxi, sometimes called also "cedar engine" and it is the *same* > Video Codec Engine in all allwinner socs. > A10/A10s/A13/A20/A23/A31/A31s/A33/A80/A80T/A83T/H3/H8 > (with some minor and or new feature hardware versions) > > How do i know? > From the kernel source code make available from allwinner. > > To the best of what could be found, this Video Codec Engine is a custom > design made by www.chipsbank.com for allwinner. And this makes believe > that is allwinner propriety and only used in allwinner socs. That's intersting. I thought, altough it seemed odd me, the VPU was an in house development of Allwinner. So the CedarX code may also be property of chipsbank. Does chipsbank provide "open" documentation? -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
