Reuse framebuffer after a kexec (amdgpu / efifb)

[Christian König]

Am 10.12.21 um 15:25 schrieb Guilherme G. Piccoli:
> On 10/12/2021 11:16, Alex Deucher wrote:> [...]
>> Why not just reload the driver after kexec?
>>
>> Alex
> Because the original issue is the kdump case, and we want a very very
> tiny kernel - also, the crash originally could have been caused by
> amdgpu itself, so if it's a GPU issue, we don't want to mess with that
> in kdump. And I confess I tried modprobe amdgpu after a kdump, no
> success - kdump won't call shutdown handlers, so GPU will be in a
> "rogue" state...
>
> My question was about regular kexec because it's much simpler usually,
> we can do whatever we want there. My line of thought was: if I make it
> work in regular kexec with a simple framebuffer, I might be able to get
> it working on kdump heheh

How about issuing a PCIe reset and re-initializing the ASIC with just 
the VBIOS?

That should be pretty straightforward I think.

Christian.