linux-kernel - Re: [PATCH 1/1] drm/amdgpu: Fix TLB flush failures after hibernation resume

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Message-ID: <ad3e0556-385b-471e-bb1c-43bd043ecf47@kernel.org>
Date: Mon, 26 Jan 2026 14:32:23 -0600
From: "Mario Limonciello (AMD) (kernel.org)" <superm1@...nel.org>
To: Alex Deucher <alexdeucher@...il.com>,
 "Ionut Nechita (Sunlight Linux)" <sunlightlinux@...il.com>
Cc: christian.koenig@....com, alexander.deucher@....com,
 amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
 ionut_n2001@...oo.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] drm/amdgpu: Fix TLB flush failures after hibernation
 resume



On 1/26/2026 2:28 PM, Mario Limonciello (AMD) (kernel.org) wrote:
> 
> 
> On 1/26/2026 2:25 PM, Alex Deucher wrote:
>> On Mon, Jan 26, 2026 at 2:52 PM Ionut Nechita (Sunlight Linux)
>> <sunlightlinux@...il.com> wrote:
>>>
>>> From: Ionut Nechita <sunlightlinux@...il.com>
>>>
>>> On Thu, Jan 8 2026 at 13:36, Christian König wrote:
>>>
>>>> Question is why the KIQ is not up and running before we do anything 
>>>> with it?
>>>
>>> Thank you for the feedback. I completely understand that my patch is
>>> just a workaround and not proper engineering - you're absolutely right
>>> that the real issue is KIQ being marked as ready before it's actually
>>> functional.
>>>
>>> I don't have experience with GPU drivers and video subsystems, so I'm
>>> not familiar with the proper initialization sequence for KIQ. I'd prefer
>>> not to keep a workaround for this issue in my tree.
>>>
>>> Is there a proper fix available, or could you point me in the right
>>> direction? I'm happy to test any patches on my AMD Cezanne (Renoir)
>>> hardware where I can reliably reproduce the issue after hibernation.
>>
>> Can you get a stack trace when this happens so we can see the call chain?
>>
>>>
>>> Also, regarding hibernation support: you mentioned that hibernation is
>>> not generally supported with the driver. Should I expect other issues
>>> beyond this TLB flush problem, or is this the main blocker?
>>
>> The biggest issue with hibernation is that it's not compatible with
>> secure boot so most distros don't officially support it.
> 
> And by extension of this it doesn't get as much testing as s2idle/s3 do.
> 
>>  The other
>> issue is that when we go into hibernation, we need to evict the
>> contents of VRAM somewhere and at the point when that happens, swap is
>> already offline.  So in a lot of cases, we don't have enough memory to
>> back up the VRAM contents.  There were patches to the Linux PM core,
>> but I can't recall if they've all landed yet. 
> 
> Yeah everything should have landed now, so swap will still be enabled.
> 
> There's also the
>> possibility that the user's swap partition is too small.
>>
>> Alex
> 
> I heard something about /sys/power/reserved_size being too small by 
> default still, so if you're having problems you might increase that.
> 
Sorry not reserved_size, /sys/power/image_size.

Here's where it was mentioned.

https://gitlab.freedesktop.org/drm/amd/-/issues/4882#note_3287247