Re: [PATCH] drm/amdgpu: Fix crash when hot unplug in BACO.

Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx> · Fri, 21 May 2021 16:37:09 -0400

Will do.

Andrey

On 2021-05-21 4:18 p.m., Alex Deucher wrote:
On Fri, May 21, 2021 at 4:14 PM Andrey Grodzovsky
<andrey.grodzovsky@xxxxxxx> wrote:
Problem:
When device goes into sleep state due to prolonged
innactivity (e.g. BACO sleep) and then hot unplugged,
PCI core will try to wake up the device as part of
unplug process. Since the device is gone all HW
programming during rpm resume fails leading
to a bad SW state later during pci remove handling.

Fix:
Use a flag we use for PCIe error recovery to avoid
accessing registres. This allows to succefully complete
rpm resume sequence and finish pci remove.
Might make sense to create a preliminary patch to change the name of
this flag to something like no_hw_access since it's not specific to
pci error handling.

Alex

P.S Must use pci_device_is_present and not drm_dev_enter/exit
here since rpm resume happens before PCI remove and so the
unplug flag is not set yet.

Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.freedesktop.org%2Fdrm%2Famd%2F-%2Fissues%2F1081&amp;data=04%7C01%7Candrey.grodzovsky%40amd.com%7C2a0ec02245b64de0139808d91c959987%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637572251118922092%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=egcYBxBU%2BkIqbEdypVueXQcWb%2Bqe%2BKCC30Mw%2FjgR6ag%3D&amp;reserved=0
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 5 +++++
  1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index d8db5929cdd9..ab95ebf56636 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -1555,6 +1555,11 @@ static int amdgpu_pmops_runtime_resume(struct device *dev)
         if (!adev->runpm)
                 return -EINVAL;

+       /* Avoids registers access if device is physically gone */
+       if (!pci_device_is_present(adev->pdev))
+               adev->in_pci_err_recovery = true;
+
+
         if (amdgpu_device_supports_px(drm_dev)) {
                 drm_dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;

--
2.25.1







