From: Felix Kuehling <felix.kuehling@amd.com>
To: "Christian König" <christian.koenig@amd.com>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
"Alex Deucher" <alexdeucher@gmail.com>
Cc: "open list:EFIFB FRAMEBUFFER DRIVER"
<linux-fbdev@vger.kernel.org>,
kernel@gpiccoli.net, "Baoquan He" <bhe@redhat.com>,
"Samuel Iglesias Gonsálvez" <siglesias@igalia.com>,
"xinhui pan" <Xinhui.Pan@amd.com>,
kexec@lists.infradead.org,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
pjones@redhat.com, "amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"Deucher, Alexander" <alexander.deucher@amd.com>,
"Dave Young" <dyoung@redhat.com>,
"Vivek Goyal" <vgoyal@redhat.com>,
"Gerd Hoffmann" <kraxel@redhat.com>
Subject: Re: Reuse framebuffer after a kexec (amdgpu / efifb)
Date: Fri, 10 Dec 2021 19:54:34 -0500 [thread overview]
Message-ID: <3988a221-2f6a-540a-3d77-18c2c67ddbe7@amd.com> (raw)
In-Reply-To: <d1de6ca3-11ae-af9e-a2fb-7bcb6fae01d6@amd.com>
On 2021-12-10 10:13 a.m., Christian König wrote:
>
>
> 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.
Do you actually need to restore the exact boot-up mode? If you have the
same framebuffer memory layout (width, height, bpp, stride) the precise
display timing doesn't really matter. So we "just" need to switch to a
mode that's compatible with the efifb framebuffer parameters and point
the display engine at the efifb as the scan-out buffer.
Regards,
Felix
>
> Christian.
next prev parent reply other threads:[~2021-12-11 0:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 16:00 Reuse framebuffer after a kexec (amdgpu / efifb) Guilherme G. Piccoli
2021-12-09 16:09 ` Christian König
2021-12-09 17:31 ` Alex Deucher
2021-12-09 17:59 ` Guilherme G. Piccoli
2021-12-09 18:06 ` Alex Deucher
2021-12-09 18:17 ` Guilherme G. Piccoli
2021-12-09 19:20 ` Alex Deucher
2021-12-10 7:19 ` Gerd Hoffmann
2021-12-10 8:24 ` Thomas Zimmermann
2021-12-10 14:08 ` Guilherme G. Piccoli
2021-12-10 14:16 ` Alex Deucher
2021-12-10 14:25 ` Guilherme G. Piccoli
2021-12-10 15:13 ` Christian König
2021-12-10 15:24 ` Guilherme G. Piccoli
2021-12-10 15:32 ` Christian König
2021-12-10 19:11 ` Alex Deucher
2021-12-11 0:54 ` Felix Kuehling [this message]
2021-12-11 9:20 ` Gerd Hoffmann
2021-12-10 19:05 ` Alex Deucher
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