system freezes when loading amdgpu

[Greg V]

On Wed, Mar 6, 2019 at 8:06 PM, Pierre DAVID <pdagog at gmail.com> wrote:
> On Wed, Mar 06, 2019 at 08:49:10AM +0000, Johannes Lundberg wrote:
>> 
>> On 3/5/19 6:07 AM, Pierre DAVID wrote:
>>> On Mon, Mar 04, 2019 at 10:02:33AM +0000, Johannes Lundberg wrote:
>>>> Hi
>>>> 
>>>> Sorry to hear you're having problems... The good news is, I think 
>>>> your
>>>> card is Southern Islands (SI) generation which means it's 
>>>> supported by
>>>> both radeonkms and amdgpu. SI should be enabled in amdgpu by 
>>>> default in
>>>> 4.16 or later.
>>>> 
>>>> To avoid any UEFI issues, I recommend booting in legacy BIOS mode 
>>>> if
>>>> possible. This way you don't have to disable syscons.
>>>> 
>>>> With drm-kmod radeonkms:
>>>> 
>>>> pkg: xf86-video-ati
>>>> xorg driver: "radeon"
>>>> 
>>>> With drm-kmod amdgpu:
>>>> 
>>>> pkg: xf86-video-amdgpu for "amdgpu", "modesetting" is included in
>>>> xorg-server.
>>>> xorg driver: "modesetting" or "amdgpu" (modesetting is probably 
>>>> better)
>>>> 
>>> 
>>> My system always boots in legacy BIOS mode (it's a pre-UEFI system).
>>> 
>>> I tried with radeonkms also: same thing occurs, the system is 
>>> freezing.
>>> 
>>>> 
>>>> "The system freezes as soon as I kldload amdgpu (or if I start X)"
>>>> 
>>>> Does this mean that you get freeze only sometimes in kldload 
>>>> amdgpu?
>>>> 
>>> 
>>> It always freezes when I kldload either amdgpu or radeonkms.
>> 
>> Hmm :(
>> 
>> Did you set all the sysctls as described in the "debugging tips" 
>> section
>> in https://wiki.freebsd.org/Graphics?
>> 
>> dev.drm.skip_ddb="1"
>> debug.debugger_on_panic=0
>> dev.drm.drm_debug_persist="1"
>> dev.drm.drm_debug=-1
>> 
>> With these set (add in /boot/loader.conf and reboot), do you get a 
>> core
>> dump or some drm log messages left in dmesg after reboot?
>> 
> 
> I didn't succeed in escaping to debugger without the dev.drm.skip_ddb 
> tunable. With (or without) this tunable set to 1, there is no crash 
> dump in /var/crash after manual reboot (via the reset button).
> 
> Here are the relevant lines in /var/log/messages.

hm, do lkpi drivers even respect dev.drm.skip_ddb?

I didn't even know that one, I used debug.debugger_on_panic=0

And keep in mind that you need a non-encrypted swap partition