<html> <head> <style></style></head> <body class='hmmessage'><div dir='ltr'> HI,all<br>      Now, my lab is using radeon_ati card。And, I need ati_card dma function。But, I do not clear that how the ati card know the dma address which alloced by kernel??<br><br>      Can any kernel drivers for radeon card give me some advise or explain the answer? <br><br>      I have read the radeon driver in kernel (/driver/gpu/drm/randeon/xxx ）and the TTM manager. So, as I know, If I use GFP_KERNEL sign to alloc memory, the radeon_card work right, but any other palce ,it failed. Why and how this happened?<br>      Is there any way to tell the dma address and ring buffer address in kernel to the radeon_card ?<br><br>     It`s so confused! Hope for your answer! <br> <br><br>Thanks so much!<br>zhiyig Si<br> </div></body> </html>