On 2020-06-10 13:48, n952162 wrote:
> On 2020-06-09 23:53, n952162 wrote:
>> I posted about this problem perhaps a year ago - when running with
>> AMDGPU, my system won't turn off, I have to hold the power button down
>> for a long time, forcing it down.
>>
>> At that time, various people commented. but AMDGPU didn't work at all
>> for me in the end, didn't talk to my HDMI display.
>>
>> I gave up on it.
>>
>> Thanks to all the great help here, I finally got my system properly
>> updated and AMDGPU working, and it  finally talks to my HDMI display.
>> But, it still doesn't shut down.
>>
>> Is it a bug?  Is my system still not right?  Is there something I have
>> to do yet?
>>
>>
>
> The following assignment is on the linux line when booting in grub:
>
> amdgpu.dc=1
>
> When I make that 0, the system shuts down properly when the power button
> is pressed.
>
> When it's 1, the system hangs after blank screen  when that button is
> pressed.
>
>
>

I found this in the AMDGPU webpage:

    /AMDGPU with Display Core was first implemented for VEGA10 (GCN5.0)
    and RAVEN (with DCN 1.0) GPUs/APUs. Kernels before version 4.17 have
    (experimental) DC support for older cards (GCN1.1 and newer) via
    command line option /amdgpu.dc=1/, which may work better than the
    older radeon kernel module. Likewise, if DC needs to be disabled for
    any particular reason, option /amdgpu.dc=0/can be used on the kernel
    command line.
    /

It's not clear to me if  DC serves a function in kernels >= 4.17 or why
it's installed as default by grub ...

I don't see anything similar in the new kernel parameters I posted to
this topic, but I do find this in my .config file:

#
# Display Engine Configuration
#
CONFIG_DRM_AMD_DC=y
CONFIG_DRM_AMD_DC_DCN1_0=y
# CONFIG_DEBUG_KERNEL_DC is not set

Was this left over from an earlier configuration and not properly
cleaned out, or is it necessary, for some reason?

Can someone explain how the amdgpu.dc=1 parameter gets passed to grub?

Thanks in advance.
//