Am 27.10.2017 um 16:58 schrieb Michel Dänzer: > On 27/10/17 04:48 PM, Christian König wrote: >> Am 27.10.2017 um 16:37 schrieb Harry Wentland: >>> On 2017-10-26 12:06 PM, Christian König wrote: >>>> From: Christian König <christian.koenig at amd.com> >>>> >>>> Just set the bit so that DC does the hardware programming. >>>> >>>> Signed-off-by: Christian König <christian.koenig at amd.com> >>>> --- >>>>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 ++ >>>>  1 file changed, 2 insertions(+) >>>> >>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >>>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >>>> index 2188f20..ed4351a 100644 >>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >>>> @@ -417,6 +417,8 @@ static int amdgpu_dm_init(struct amdgpu_device >>>> *adev) >>>>       init_data.dce_environment = DCE_ENV_PRODUCTION_DRV; >>>>  +   init_data.flags.gpu_vm_support = true; >>>> + >>> Hi Christian, >>> >>> what ASIC has this been tested on? >> Carizzo. >> >>> I'm not sure that this won't break dGPU. dGPU doesn't have vm_support >>> but I think DC will still try to write the same registers as for CZ on >>> dGPU if we enable this. We at least need to make sure it doesn't blow up. >> Yeah, as Tom already stumbled over as well it causes a warning on Tonga. >> Currently giving it a spin on Polaris. >> >>> As for Raven we use this flag on Windows but only tested the case >>> where VM is actually programmed. If VM isn't programmed it might still >>> work but we'd need to give that a spin. >> Without this flag tilling fails and only displays a quite unusual pattern. >> >> I would actually prefer if we can completely remove this flag and >> instead always enable the VM programming on supported hardware. >> >> Is there any downside on doing so? > Is there a particular use-case for scanout from system memory with a > dGPU? Otherwise I suspect it's better not to bother, because the failure > mode might be pretty bad if the PCIe link can't keep up with scanout. That's true and I actually didn't want to suggest that we scanout from system memory on dGPUs. But setting up the tilling information in the DCE/DCN VM block anyway looks harmless to me. And scanning out from scattered VRAM at some point still seems to make sense to me. Regards, Christian.
