George, 1) The constraint for the DSP algorithms (actually the DSP core itself) is that they have to work on contiguous buffers. The vpfe device driver allocates it's own contiguous frame buffers in kernel mode and doesn't need CMEM.
2) Codec Engine doesn't copy the frame buffers, it just passes a pointer. The DSP and ARM *physical* memory maps are identical on Davinci. 3) loadmodules.sh contains the worst case for any of the encode, decode or encodedecode demos running (but not simultaneously). If you only ever use one of the demos your pool selection would look different. For the demos, you can find every Memory_contigAlloc() call and see what the worst case buffer sizes are and put these in loadmodules.sh. 4) Non-cacheable from the ARM, but Codec Engine does manage cache for these buffers from a DSP standpoint. Regards, Niclas -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of George Gu Sent: Friday, December 15, 2006 8:24 AM To: [email protected] Subject: CMEM and video driver issues, need your help All, There are some questions about CMEM and video driver, which need your help. 1. Does vpfe capture buffers located in Linux Memory space? If yes, how does them be transferred to DSP? I guess CODEC Engine will copy them into CMEM buffer pool first and then DSP will use these data in CMEM buffer pool, is it right? 2. Base on question 1, CODEC ENGINE copy the capture data use DMA? or memory copy? 3. When insert CMEM.ko, there are some parameters, such as pool counts and pool size, how can I determine these parameters when I use a certain codec combos, such as H264 encoder+ H264 decoder+mpeg4 decoder??? In TI's H264 encodedecode demo, I found "pools=1x3145728,3x829440,1x61440,1x10240" (loadmodules.sh), why there is a pool with 3145728 byte? 4. The CMEM memory is non-cacheable both for ARM and DSP? Thanks very much. George Gu (Xiangyu Gu) Wintech Digital System Co. Beijing, China Ph: 8610-8278-2828 ext.168 Fax: 8610-8278-0028 http://www.wintechdigtal.com _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
