Re: 回复: [PATCH] drm/amd/amdgpu: disable GFXOFF around debugfs access to MMIO

Fri Feb 21 15:39:53 UTC 2020

[AMD Public Use]

If we are trying to debug a reproducible hang, probably best to just to disable gfxoff before messing with it to remove that as a factor.  Otherwise, the method included in this patch is the proper way to disable/enable GFXOFF dynamically.

Alex

________________________________
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of Christian König <ckoenig.leichtzumerken at gmail.com>
Sent: Friday, February 21, 2020 10:27 AM
To: Huang, Ray <Ray.Huang at amd.com>; Liu, Monk <Monk.Liu at amd.com>
Cc: StDenis, Tom <Tom.StDenis at amd.com>; Alex Deucher <alexdeucher at gmail.com>; amd-gfx list <amd-gfx at lists.freedesktop.org>
Subject: Re: 回复: [PATCH] drm/amd/amdgpu: disable GFXOFF around debugfs access to MMIO

Am 21.02.20 um 16:23 schrieb Huang Rui:
> On Fri, Feb 21, 2020 at 11:18:07PM +0800, Liu, Monk wrote:
>> Better not use KIQ, because when you use debugfs to read register you usually hit a hang, and by that case KIQ probably already die
> If CP is busy, the gfx should be in "on" state at that time, we needn't use KIQ.

Yeah, but how do you detect that? Do we have a way to wake up the CP
without asking power management to do so?

Cause the register debug interface is meant to be used when the ASIC is
completed locked up. Sending messages to the SMU is not really going to
work in that situation.

Regards,
Christian.

>
> Thanks,
> Ray
>
>> -----邮件原件-----
>> 发件人: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> 代表 Huang Rui
>> 发送时间: 2020年2月21日 22:34
>> 收件人: StDenis, Tom <Tom.StDenis at amd.com>
>> 抄送: Alex Deucher <alexdeucher at gmail.com>; amd-gfx list <amd-gfx at lists.freedesktop.org>
>> 主题: Re: [PATCH] drm/amd/amdgpu: disable GFXOFF around debugfs access to MMIO
>>
>> On Wed, Feb 19, 2020 at 10:09:46AM -0500, Tom St Denis wrote:
>>> I got some messages after a while:
>>>
>>> [  741.788564] Failed to send Message 8.
>>> [  746.671509] Failed to send Message 8.
>>> [  748.749673] Failed to send Message 2b.
>>> [  759.245414] Failed to send Message 7.
>>> [  763.216902] Failed to send Message 2a.
>>>
>>> Are there any additional locks that should be held?  Because some
>>> commands like --top or --waves can do a lot of distinct read
>>> operations (causing a lot of enable/disable calls).
>>>
>>> I'm going to sit on this a bit since I don't think the patch is ready
>>> for pushing out.
>>>
>> How about use RREG32_KIQ and WREG32_KIQ?
>>
>> Thanks,
>> Ray
>>
>>> Tom
>>>
>>> On 2020-02-19 10:07 a.m., Alex Deucher wrote:
>>>> On Wed, Feb 19, 2020 at 10:04 AM Tom St Denis <tom.stdenis at amd.com> wrote:
>>>>> Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
>>>> Please add a patch description.  With that fixed:
>>>> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
>>>>
>>>>> ---
>>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 3 +++
>>>>>    1 file changed, 3 insertions(+)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>> index 7379910790c9..66f763300c96 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
>>>>> @@ -169,6 +169,7 @@ static int  amdgpu_debugfs_process_reg_op(bool read, struct file *f,
>>>>>           if (pm_pg_lock)
>>>>>                   mutex_lock(&adev->pm.mutex);
>>>>>
>>>>> +       amdgpu_gfx_off_ctrl(adev, false);
>>>>>           while (size) {
>>>>>                   uint32_t value;
>>>>>
>>>>> @@ -192,6 +193,8 @@ static int  amdgpu_debugfs_process_reg_op(bool read, struct file *f,
>>>>>           }
>>>>>
>>>>>    end:
>>>>> +       amdgpu_gfx_off_ctrl(adev, true);
>>>>> +
>>>>>           if (use_bank) {
>>>>>                   amdgpu_gfx_select_se_sh(adev, 0xffffffff, 0xffffffff, 0xffffffff);
>>>>>                   mutex_unlock(&adev->grbm_idx_mutex);
>>>>> --
>>>>> 2.24.1
>>>>>
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