amdgpu vs kexec

[Mario Limonciello]

On 6/18/2025 4:05 AM, Christian König wrote:
> On 6/18/25 10:51, Peter Zijlstra wrote:
>> On Tue, Jun 17, 2025 at 09:12:12PM -0500, Mario Limonciello wrote:
>>
>>> How about if we reset before the kexec?  There is a symbol for drivers to
>>> use to know they're about to go through kexec to do $THINGS.
>>>
>>> Something like this:
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> index 0fc0eeedc6461..2b1216b14d618 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>> @@ -34,6 +34,7 @@
>>>
>>>   #include <linux/cc_platform.h>
>>>   #include <linux/dynamic_debug.h>
>>> +#include <linux/kexec.h>
>>>   #include <linux/module.h>
>>>   #include <linux/mmu_notifier.h>
>>>   #include <linux/pm_runtime.h>
>>> @@ -2544,6 +2545,9 @@ amdgpu_pci_shutdown(struct pci_dev *pdev)
>>>                  adev->mp1_state = PP_MP1_STATE_UNLOAD;
>>>          amdgpu_device_ip_suspend(adev);
>>>          adev->mp1_state = PP_MP1_STATE_NONE;
>>> +
>>> +       if (kexec_in_progress)
>>> +               amdgpu_asic_reset(adev);
>>>   }
>>>
>>>   static int amdgpu_pmops_prepare(struct device *dev)
>>
>> I will throw this in the dev kernel... I'll let you know.
> 
> Mhm if the drivers are informed about the kexec

It looks like PeterZ found the symbol isn't exported; but that's not to 
say it "can't be" if it fixes this issue.

> then we could also send the unload/reset packet only to the PSP IIRC.
> 
> That might have a better chance of succeeding than a full ASIC reset.
> 
> Lijo should know more about that.
> 
> Regards,
> Christian.

Another idea is to do a FLR on the way down.