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On 2020-06-10 18:23, n952162 wrote: |
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> On 2020-06-10 13:48, n952162 wrote: |
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>> On 2020-06-09 23:53, n952162 wrote: |
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>>> I posted about this problem perhaps a year ago - when running with |
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>>> AMDGPU, my system won't turn off, I have to hold the power button down |
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>>> for a long time, forcing it down. |
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>>> |
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>>> At that time, various people commented. but AMDGPU didn't work at all |
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>>> for me in the end, didn't talk to my HDMI display. |
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>>> |
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>>> I gave up on it. |
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>>> |
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>>> Thanks to all the great help here, I finally got my system properly |
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>>> updated and AMDGPU working, and it finally talks to my HDMI display. |
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>>> But, it still doesn't shut down. |
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>>> |
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>>> Is it a bug? Is my system still not right? Is there something I have |
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>>> to do yet? |
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>>> |
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>>> |
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>> |
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>> The following assignment is on the linux line when booting in grub: |
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>> |
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>> amdgpu.dc=1 |
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>> |
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>> When I make that 0, the system shuts down properly when the power button |
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>> is pressed. |
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>> |
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>> When it's 1, the system hangs after blank screen when that button is |
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>> pressed. |
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>> |
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>> |
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>> |
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> |
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> I found this in the AMDGPU webpage: |
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> |
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> /AMDGPU with Display Core was first implemented for VEGA10 |
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> (GCN5.0) and RAVEN (with DCN 1.0) GPUs/APUs. Kernels before |
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> version 4.17 have (experimental) DC support for older cards |
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> (GCN1.1 and newer) via command line option /amdgpu.dc=1/, which |
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> may work better than the older radeon kernel module. Likewise, if |
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> DC needs to be disabled for any particular reason, option |
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> /amdgpu.dc=0/can be used on the kernel command line. |
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> / |
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> |
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> It's not clear to me if DC serves a function in kernels >= 4.17 or |
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> why it's installed as default by grub ... |
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> |
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> I don't see anything similar in the new kernel parameters I posted to |
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> this topic, but I do find this in my .config file: |
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> |
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> # |
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> # Display Engine Configuration |
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> # |
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> CONFIG_DRM_AMD_DC=y |
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> CONFIG_DRM_AMD_DC_DCN1_0=y |
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> # CONFIG_DEBUG_KERNEL_DC is not set |
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> |
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> Was this left over from an earlier configuration and not properly |
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> cleaned out, or is it necessary, for some reason? |
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> |
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> Can someone explain how the amdgpu.dc=1 parameter gets passed to grub? |
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> |
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> |
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|
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Okay, I found out how amdgpu.dc=1 gets into grub - via |
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/etc/default/grub. I'm not sure who put it there - was it the kernel |
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make process? |
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|
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Note that even with amdgpu.dc=0, I still have (finally!) HDMI output to |
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my monitor. There's a lot of talk on the internet about whether |
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amdgpu.dc=1 is good or bad, but nobody seems to know or explain what |
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it's about, or the role of Display Core WRT to AMDGPU. |
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|
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The only important thing unresolved for me now is whether I still need |
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those DRM_AMD_DC kernel variables, above. |