On 22/06/10 20:32, Dave Airlie wrote: > On Tue, Jun 22, 2010 at 3:59 PM, FUJITA Tomonori > <fujita.tomonori at lab.ntt.co.jp> wrote: >> On Mon, 21 Jun 2010 17:19:43 -0400 >> Matt Turner<mattst88 at gmail.com> wrote: >> >>> Michael Cree and I have been debugging FDO bug 26403 [1]. I tried >>> booting with `radeon.test=1` and found this, which I think is related:
Note that my radeon card is PCI whereas I think Matt may be using an AGP card. My logs are very similar to Matt's except I don't see the following line: >>>> pci_map_single failed: could not allocate dma page tables >> This happens in the latest git, right? Indeed, testing 2.6.35-rc3 (plus a couple or so extra patches to fix unrelated compile errors). >> Is this a regression (what kernel version worked)? >> >> Seems that the IOMMU can't find 128 pages. It's likely due to: >> >> - out of the IOMMU space (possibly someone doesn't free the IOMMU >> space). >> >> or >> >> - the mapping parameters (such as align) aren't appropriate so the >> IOMMU can't find space. > > I don't think KMS drivers have ever worked on alpha so its not a > regression, they are working fine on x86 + powerpc and sparc has been > run at least once. KMS on the console boot up has worked since about 2.6.32, but starting up the X server has always failed and, in my case, the system becomes unstable and eventually OOPs. > I suspect we are simply hitting the limits of the iommu, how big an > address space does it handle? since generally graphics drivers try to > bind a lot of things to the GART. No idea on the address space limit. I applied the patch of Fujita that logs all IOMMU allocations, and also inserted some extra printks in the ttm kernel code so that I could see which routines failed and the error code returned. Running the radeon test on boot exhibits the following: [ 238.712768] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset 0x1a312000 [ 239.281127] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset 0x1a412000 [ 239.281127] ttm_tt_bind belched -12 [ 239.282104] ttm_bo_handle_move_mem belched -12 [ 239.282104] ttm_bo_move_buffer belched -12 [ 239.282104] ttm_bo_validate belched -12 [ 239.282104] radeon 0000:01:00.0: object_init failed for (1048576, 0x00000002) err=-12 [ 239.282104] [drm:radeon_test_moves] *ERROR* Failed to create GTT object 419 [ 239.399291] Error while testing BO move. Note that no IOMMU allocations are printed while radeon_test_moves is running so iommu_arena_alloc doesn't appear to be called. Also the error code returned up to radeon_test_moves is -12 which is ENOMEM. So does appear to be some memory limit. > It might be worth limiting the PCIGART in radeon to 32MB to see if the > lower limit helps. So, how does one do that? Cheers Michael.
