Re: 回复: [REGRESSION] amdgpu: async system error exception from hdp_v5_0_flush_hdp()

["Christian König" <christian.koenig@amd.com>]

On 4/22/25 17:59, Alexey Klimov wrote:
> On Tue Apr 22, 2025 at 2:00 PM BST, Alex Deucher wrote:
>> On Mon, Apr 21, 2025 at 10:21 PM Alexey Klimov <alexey.klimov@linaro.org> wrote:
>>>
>>> On Thu Apr 17, 2025 at 2:08 PM BST, Alex Deucher wrote:
>>>> On Wed, Apr 16, 2025 at 8:43 PM Fugang Duan <fugang.duan@cixtech.com> wrote:
>>>>>
>>>>> 发件人: Alex Deucher <alexdeucher@gmail.com> 发送时间: 2025年4月16日 22:49
>>>>>> 收件人: Alexey Klimov <alexey.klimov@linaro.org>
>>>>>> On Wed, Apr 16, 2025 at 9:48 AM Alexey Klimov <alexey.klimov@linaro.org> wrote:
>>>>>>>
>>>>>>> On Wed Apr 16, 2025 at 4:12 AM BST, Fugang Duan wrote:
>>>>>>>> 发件人: Alexey Klimov <alexey.klimov@linaro.org> 发送时间: 2025年4月16
>>>>>> 日 2:28
>>>>>>>>> #regzbot introduced: v6.12..v6.13
>>>>>>>>> The only change related to hdp_v5_0_flush_hdp() was
>>>>>>>>> cf424020e040 drm/amdgpu/hdp5.0: do a posting read when flushing HDP
>>>>>>>>>
>>>>>>>>> Reverting that commit ^^ did help and resolved that problem. Before
> 
> [..]
> 
>>>> OK.  that patch won't change anything then.  Can you try this patch instead?
>>>
>>> Config I am using is basically defconfig wrt memory parameters, yeah, i use 4k.
>>>
>>> So I tested that patch, thank you, and some other different configurations --
>>> nothing helped. Exactly the same behaviour with the same backtrace.
>>
>> Did you test the first (4k check) or the second (don't remap on ARM) patch?
> 
> The second one. I think you mentioned that first one won't help for 4k pages.
> 
> 
>>> So it seems that it is firmware problem after all?
>>
>> There is no GPU firmware involved in this operation.  It's just a
>> posted write.  E.g., we write to a register to flush the HDP write
>> queue and then read the register back to make sure the write posted.
>> If the second patch didn't help, then perhaps there is some issue with
>> MMIO access on your platform?
> 
> I didn't mean GPU firmware at all. I only had uefi/EL3 firmwares in mind.
> 
> Completely out of the blue, based on nothing, do you think that
> adding delay/some mem barrier between write and read might help?

That would still be quite some platform bug.

> I wonder if host data path code should be executed during common desktop
> usage as a common user then why it doesn't break later.

Maybe it's some kind of write/read re-ordering issue.

 But yeah, I also think this is this motherboard problem. Thank you.

You should probably ping some ARM guys to figure out what the fault code actually means.

Regards,
Christian.

> 
> Thanks,
> Alexey
>