I have studied the v4l2 display driver,it supported V4L2_MEMORY_USERPTR 
mothod,it seemed can accept a buffer address but it must be mmaped to the 
display buffer first,So the captured buffer datas must translate to the mmaped 
buffer,so the result is equal  to mmap display buffer directly.

 V4L2_MEMORY_MMAP :     v4l2 capture buffer->address1(mmaped) ->  EDMA->   
address2 (mmaped)<-v4l2 or fbdev buffer 
 V4L2_MEMORY_USERPTR  :v4l2 capture buffer->address1(mmaped) ->  EDMA->   
address2 (mmaped)->v4l2 or fbdev buffer 

2009-07-09 



zuowenping 



发件人: zuowenping 
发送时间: 2009-07-09  19:35:44 
收件人: davinci-linux-open-source 
抄送: 
主题: Can i give the capture buffer address to fbdev or v4l2 for displaydirectly? 
 
dear all:
I am now using dm355 for capturing 640x480(30 frame / second)  picture and 
displayed in svga mode 800x600(60 frame / second) by ths8200.if i used edma  to 
translated data from v4l2 caputured buffer to frame buffer, It will emerge 
noised pictures,i have set PBBPR register with value 30 .but if i change to 
displayed in vga mode  640x480(60 f/s),it seem ok!it seemed the ddr speed(171M) 
is not enough! but My project GUI(osd) must be set as 800x600,So i have to 
change displaying to svga.I don't want to used edma, then can i  give the 
displayer driver(fbdev or v4l2) my caputre buffer address directly?

2009-07-09 



zuowenping 
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