Thanks for you reply! I use PCI――MMIO to access VRAM and GTT areas. And for ring_buffer, it alloced from the vmalloc―area and vmap to the physical address using page table.
If enable the radeon_benchmark, it first to prepare the dma channel. "set_tex_resource(), set_render_target(), cp_set_surface_sync()" ,such functions only write ring_buffer. The ring_buffer is vma-area, even it map to physical area. But for radeon_card, how it know the physical-area?? The question is same to the SCRACH test, ring_test. Why I write into ring_buffer,then the card register will know the value "deadbeef" ?? Do I not understand the real card work? ring_test?? > Date: Wed, 13 Jun 2012 09:57:28 -0400 > From: konrad.w...@oracle.com > To: sizhiy...@hotmail.com > CC: dri-devel@lists.freedesktop.org > Subject: Re: about_radeon_dma > > On Wed, Jun 13, 2012 at 09:44:19AM +0800, llittle了了 wrote: > > > > HI,all > > 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?? > > By using the PCI API. > > > > > > Can any kernel drivers for radeon card give me some advise or explain > > the answer? > > > > 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? > > Is there any way to tell the dma address and ring buffer address in > > kernel to the radeon_card ? > > > > It`s so confused! Hope for your answer! > > > > > > Thanks so much! > > zhiyig Si > > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > http://lists.freedesktop.org/mailman/listinfo/dri-devel >
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