On Fri, Jan 5, 2024 at 9:16 AM Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote: > > Am 21.12.23 um 02:58 schrieb Ma, Jun: > > Hi Christian, > > > > > > On 12/20/2023 10:10 PM, Christian König wrote: > >> Am 19.12.23 um 06:58 schrieb Ma Jun: > >>> Print a warnning message if the system can't access > >>> the resize bar register when using large bar. > >> Well pretty clear NAK, we have embedded use cases where this would > >> trigger an incorrect warning. > >> > >> What should that be good for in the first place? > >> > > Some customer platforms do not enable mmconfig for various reasons, such as > > bios bug, and therefore cannot access the GPU extend configuration > > space through mmio. > > > > Therefore, when the system enters the d3cold state and resumes, > > the amdgpu driver fails to resume because the extend configuration > > space registers of GPU can't be restored. At this point, Usually we > > only see some failure dmesg log printed by amdgpu driver, it is > > difficult to find the root cause. > > > > So I thought it would be helpful to print some warning messages at > > the beginning to identify problems quickly. > > Interesting bug, but we can't do this here. We have a couple of devices > where the REBAR cap isn't enabled for some reason (or not correctly > enabled). > > In this case this would print a warning even when there isn't anything > wrong. > > What we could potentially do is to check for the MSI extension, that > should always be there if I'm not completely mistaken. > > But how does this hardware platform even works without the extended mmio > space? I mean we can't even enable/disable MSI in that configuration if > I'm not completely mistaken. That system is probably similar to what Mario mentioned: https://lore.kernel.org/linux-pci/20231215220343.22523-1-mario.limonciello@xxxxxxx/ Alex > > Regards, > Christian. > > > > > Regards, > > Ma Jun > > > >> Regards, > >> Christian. > >> > >>> Signed-off-by: Ma Jun <Jun.Ma2@xxxxxxx> > >>> --- > >>> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 10 +++++++++- > >>> 1 file changed, 9 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > >>> index 4b694696930e..e7aedb4bd66e 100644 > >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > >>> @@ -1417,6 +1417,12 @@ void amdgpu_device_wb_free(struct amdgpu_device *adev, u32 wb) > >>> __clear_bit(wb, adev->wb.used); > >>> } > >>> > >>> +static inline void amdgpu_find_rb_register(struct amdgpu_device *adev) > >>> +{ > >>> + if (!pci_find_ext_capability(adev->pdev, PCI_EXT_CAP_ID_REBAR)) > >>> + DRM_WARN("System can't access the resize bar register,please check!!\n"); > >>> +} > >>> + > >>> /** > >>> * amdgpu_device_resize_fb_bar - try to resize FB BAR > >>> * > >>> @@ -1444,8 +1450,10 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev) > >>> > >>> /* skip if the bios has already enabled large BAR */ > >>> if (adev->gmc.real_vram_size && > >>> - (pci_resource_len(adev->pdev, 0) >= adev->gmc.real_vram_size)) > >>> + (pci_resource_len(adev->pdev, 0) >= adev->gmc.real_vram_size)) { > >>> + amdgpu_find_rb_register(adev); > >>> return 0; > >>> + } > >>> > >>> /* Check if the root BUS has 64bit memory resources */ > >>> root = adev->pdev->bus; >
