<html> <head> <style></style></head> <body class='hmmessage'><div dir='ltr'> Yes, I transplant the radeon_driver from 64bit_kernel to a mini 32bit_os. The purpose is to open radeon_benchmark  or Xorg in the mini_32bit_os. So, I think ring_test success means GPU  work correctly and smmothly. But ,my ring_test in the mini_32bit_os does not success. When I read scratch register, it`s not the value wrote into the memory location.So, I think the address space does not map correct. <pre>>> |--系统内存--|--显存--|--GTT内存--| >> 0 256M 384M 896M</pre>Such memory alloction in my mini32bit_os has been build up. There are  differences between linux-kernel and my mini32bit_os : first,  mymini32bit_os does not have TTM; second, the mini32bit_os use 0x8000,0000-----0x9000,0000 virtual address which map to 0x0----0x1000,0000 physical address . While linux-kernel use 0x9800,0000,fc24,0000——0x9800,0000,ff00,0000 CPU vritual address which map to 0x0000,0000,fc24,0000——0x0000,0000,ff00,0000 physical address.I have 2g memory. I also use gart_table to tell GPU my mini32bit_os address. set_gart_pages. But ring_test still does not work. If we can use gart_table to tell GPU the ring_buffer memory location, I alloc the ring_buffer from the low 16M memory, then fill the gart_table, GPU would konw that address and ring_test would sucess. But, when I use the low 16M memory for ring_buffer, ring_test failed. I have reserved the low 16M memory  at the boot time. That is the exactly confused me. Why? I move ring_buffer any other palace, ring_test will not work? <div><div id="SkyDrivePlaceholder"></div>> Date: Wed, 13 Jun 2012 22:35:45 -0400 > Subject: Re: about_radeon_dma > From: alexdeucher@gmail.com > To: sizhiying@hotmail.com > CC: konrad.wilk@oracle.com; dri-devel@lists.freedesktop.org > > On Wed, Jun 13, 2012 at 9:55 PM, llittle了了 <sizhiying@hotmail.com> wrote: > > 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?? > > What exactly are you trying to accomplish? The GPU has it's own > internal address space that is used by on chip clients. Within that > address space you map can map vram, AGP, and on-chip gart apertures. > The on chip gart aperture lets you map system pages into a contiguous > linear aperture within the GPU's address space. Once you have these > apertures set up, internal GPU clients need only point to the > appropriate internal address to access a buffer in either system ram > (via on-chip gart or AGP) or vram. For example, you can store > textures in system memory pages and point the texture hardware at them > and the chip will read from those pages and use the textures on a quad > rendered to vram, or vice versa. > > Command are sent to the GPU via a command processor (CP) that fetches > commands from a ring buffer. You write the commands into the ring > buffer and update the write pointer. The CP then executes the > commands in the ring buffer until the read pointer and write pointer > both point to the same index. At that point the CP stops and waits > until the write pointer is updated again. In the ring test, we put > command packets on the ring to write to a scatch register or memory > location. When the CP is done, we check the register or memory > location to make sure it was properly updated. That way we know the > ring buffer is working. > > Alex > > > > > > >> Date: Wed, 13 Jun 2012 09:57:28 -0400 > >> From: konrad.wilk@oracle.com > >> To: sizhiying@hotmail.com > >> CC: dri-devel@lists.freedesktop.org > >> Subject: Re: about_radeon_dma > >> > >> On Wed, Jun 1 3, 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 > >> > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > http://lists.freedesktop.org/mailman/listinfo/dri-devel > > </div> </div></body> </html>