Bug 200695

Summary: Blank screen on RX 580 with amdgpu.dc=1 enabled (no displays detected)
Product: Drivers Reporter: Claude Heiland-Allen (claude)
Component: Video(DRI - non Intel)Assignee: drivers_video-dri
Status: NEW ---    
Severity: normal CC: 2kbrian, adia, alexdeucher, alexvkaam, andrey.arapov, anode.dev, babgozdtb, bjo, exiele.dfo, farshad, harry.wentland, lukas.fink1, magicmyth, mericsakarya, nicholas.kazlauskas, smirky, sndirsch, ty, virtuousfox
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 4.17.19, 4.18.5 -- 4.18.20, 4.19-rc1 -- 4.19.89, 4.20-rc1 -- 4.20.17, 5.0-rc1 -- 5.0.5, 5.1-rc3, 5.3.9, 5.3.16, 5.4.3, 5.5-rc2 Tree: Mainline
Regression: No
Attachments: dmesg after boot with amdgpu.dc=1 amdgpu.dc_log=1 drm.debug=6
dmesg after replugging monitor with amdgpu.dc=1 amdgpu.dc_log=1 drm.debug=6
dmesg after boot with amdgpu.dc=0 drm.debug=6
Xorg.0.log with amdgpu=1
Xorg.0.log with amdgpu.dc=0
xorg.conf
dmesg for 4.19-rc1 amdgpu.dc=1 amdgpu.dc_log=1 drm.debug=6
dmesg logs after booting to X with displays connected to both DVI and HDMI
5.4.0 amdgpu.dc=0 drm.debug=0xe
5.4.0 amdgpu.dc=1 drm.debug=0xe

Description Claude Heiland-Allen 2018-07-31 18:32:58 UTC
Created attachment 277633 [details]
dmesg after boot with amdgpu.dc=1 amdgpu.dc_log=1 drm.debug=6

When amdgpu.dc=1 is initialized at boot, the console goes blank as it thinks all displays are disconnected.  Xorg is not able to enable the display either.  With amdgpu.dc=0 all is fine.  Tried with various (mostly Debian) kernels from 4.16 through 4.18~rc4, all have the issue.  I built a 4.18~rc7 from kernel.org to rule out Debian patches being the issue and will provide logs.
Comment 1 Claude Heiland-Allen 2018-07-31 18:33:49 UTC
Created attachment 277635 [details]
dmesg after replugging monitor with amdgpu.dc=1 amdgpu.dc_log=1 drm.debug=6
Comment 2 Claude Heiland-Allen 2018-07-31 18:34:24 UTC
Created attachment 277637 [details]
dmesg after boot with amdgpu.dc=0 drm.debug=6
Comment 3 Claude Heiland-Allen 2018-07-31 18:37:12 UTC
Created attachment 277639 [details]
Xorg.0.log with amdgpu=1
Comment 4 Claude Heiland-Allen 2018-07-31 18:37:40 UTC
Created attachment 277641 [details]
Xorg.0.log with amdgpu.dc=0
Comment 5 Claude Heiland-Allen 2018-07-31 18:38:49 UTC
Created attachment 277643 [details]
xorg.conf
Comment 6 Claude Heiland-Allen 2018-08-28 15:40:23 UTC
still an issue with 4.18.5

still an issue with 4.19-rc1, I will attach dmesg
Comment 7 Claude Heiland-Allen 2018-08-28 15:42:13 UTC
Created attachment 278167 [details]
dmesg for 4.19-rc1 amdgpu.dc=1 amdgpu.dc_log=1 drm.debug=6
Comment 8 Claude Heiland-Allen 2018-09-06 06:51:53 UTC
still an issue with 4.18.6

still an issue with 4.19-rc2

if you need more logs, let me know which boot options I should add

console displays fine on first boot but after a few seconds dmesg reports
[    5.318879] [drm] Cannot find any crtc or sizes
and screen goes blank, and the monitor turns itself off after a few moments
Comment 9 Claude Heiland-Allen 2018-09-10 13:45:33 UTC
still an issue with 4.18.7

still an issue with 4.19-rc3
Comment 10 Andrey Arapov 2018-09-17 17:46:20 UTC
Could you try enabling CONFIG_DRM_AMD_DC_PRE_VEGA option when rebuilding the kernel and see if that works with amdgpu.dc=1 ?
Comment 11 Andrey Arapov 2018-09-17 18:09:29 UTC
Oh, that option is gone from 4.18.
Comment 12 Claude Heiland-Allen 2018-09-18 02:10:01 UTC
not an issue with 4.14.70 (I think it does not have amdgpu.dc as an option?)

still an issue with 4.17.19 compiled with CONFIG_DRM_AMD_DC_PRE_VEGA=y

still an issue with 4.18.8

still an issue with 4.19-rc4
Comment 13 Andrey Arapov 2018-09-18 13:43:20 UTC
Could you please try reverting this commit https://github.com/torvalds/linux/commit/e03fd3f300f6184c1264186a4c815e93bf658abb , rebuilding your kernel and let us know if it fixes your issue?

Not sure if your problem is related to mine here https://github.com/Dunedan/mbp-2016-linux/issues/73#issuecomment-422397681

But it has helped in my case.
Comment 14 Claude Heiland-Allen 2018-09-18 15:02:45 UTC
I checked out linux v4.19-rc4 from git, then reverted that commit - no change, display goes blank about 5 seconds into boot.

I noticed something else in the dmesg (it was there in 4.19-rc1,rc2,rc3,rc4,rc4 with reverted commit, but not earlier versions):

[    5.109572] amdgpu: [powerplay] Failed to retrieve minimum clocks.
[    5.109577] amdgpu: [powerplay] Error in phm_get_clock_info 
[    5.109627] [drm] DM_PPLIB: values for Engine clock
[    5.109629] [drm] DM_PPLIB:	 300000
[    5.109631] [drm] DM_PPLIB:	 600000
[    5.109632] [drm] DM_PPLIB:	 900000
[    5.109633] [drm] DM_PPLIB:	 1145000
[    5.109634] [drm] DM_PPLIB:	 1215000
[    5.109636] [drm] DM_PPLIB:	 1257000
[    5.109637] [drm] DM_PPLIB:	 1300000
[    5.109638] [drm] DM_PPLIB:	 1366000
[    5.109640] [drm] DM_PPLIB: Validation clocks:
[    5.109641] [drm] DM_PPLIB:    engine_max_clock: 136600
[    5.109642] [drm] DM_PPLIB:    memory_max_clock: 200000
[    5.109644] [drm] DM_PPLIB:    level           : 8
[    5.109646] [drm] DM_PPLIB: values for Memory clock
[    5.109647] [drm] DM_PPLIB:	 300000
[    5.109648] [drm] DM_PPLIB:	 1000000
[    5.109649] [drm] DM_PPLIB:	 2000000
[    5.109651] [drm] DM_PPLIB: Validation clocks:
[    5.109652] [drm] DM_PPLIB:    engine_max_clock: 136600
[    5.109653] [drm] DM_PPLIB:    memory_max_clock: 200000
[    5.109655] [drm] DM_PPLIB:    level           : 8
[    5.124083] [drm] Display Core initialized with v3.1.59!

The last (largest) value for "engine clock" and "memory clock" are 10x the validation values for "engine clock max" and "memory clock max".  I see in the amd/powerplay sources some values are in units of 10kHz, some in units of 1kHz(?) - maybe a conversion was missed somewhere? Or maybe the printout is totally normal and I know nothing :)

The error message common to all kernels with amdgpu.dc=1 since 4.17 is:

[    5.256378] [drm] Cannot find any crtc or sizes
Comment 15 Claude Heiland-Allen 2018-10-01 17:30:48 UTC
still an issue in 4.18.9
still an issue in 4.18.10
still an issue in 4.18.11
still an issue in 4.19-rc5
still an issue in 4.19-rc6
Comment 16 Claude Heiland-Allen 2018-10-10 21:16:44 UTC
still an issue in 4.18.12
still an issue in 4.18.13
still an issue in 4.19-rc7
Comment 17 Claude Heiland-Allen 2018-10-22 18:52:39 UTC
still an issue in 4.18.14
still an issue in 4.18.15
still an issue in 4.18.16
still an issue in 4.19-rc8
still an issue in 4.19
Comment 18 Claude Heiland-Allen 2018-11-06 16:13:10 UTC
still an issue in 4.18.17
still an issue in 4.19.1
still an issue in 4.20-rc1 (configured with HSA enabled)
Comment 19 Claude Heiland-Allen 2018-11-13 19:54:47 UTC
still an issue in 4.18.18
still an issue in 4.20-rc2
Comment 20 Claude Heiland-Allen 2018-11-19 18:15:05 UTC
still an issue in 4.18.19
still an issue in 4.19.2
still an issue in 4.20-rc3
Comment 21 Claude Heiland-Allen 2018-12-04 23:12:59 UTC
still an issue in 4.18.20 4.19.3 4.19.4 4.19.5 4.19.6 4.20-rc4 4.20-rc5
Comment 22 Dev Bazilio 2018-12-28 06:07:45 UTC
> amdgpu: [powerplay] Failed to retrieve minimum clocks. 
Confirmed, I started getting this error and entire black screen from 4.19.4 and all latest kernels

product: Lexa PRO [Radeon RX 550/550X]
vendor: Advanced Micro Devices, Inc. [AMD/ATI]
Comment 23 Alex van Kaam 2019-01-12 11:18:30 UTC
same issue with an HP Notebook - 17-ca0710nd
Advanced Micro Devices, Inc. [AMD/ATI] Stoney [Radeon R2/R3/R4/R5 Graphics] [1002:98e4] (rev da)
Kernel 4.19.12

need to use amdgpu.dc=0 OR video=1024x768M@60m to get the build in screen to work
Comment 24 Claude Heiland-Allen 2019-01-13 19:35:39 UTC
still an issue in 4.19.15 4.20.2 5.0-rc1 (I didn't check intermediate versions since comment 21 above https://bugzilla.kernel.org/show_bug.cgi?id=200695#c21 )

[drm] Cannot find any crtc or sizes

followed by screen going blank, monitor turning off, no display detected
Comment 25 Claude Heiland-Allen 2019-02-25 17:51:28 UTC
still an issue in 4.19.25 4.20.12 5.0-rc8 (I didn't check intermediate versions since comment 24 above)
Comment 26 Alex van Kaam 2019-02-26 16:43:44 UTC
hi

on request of the people over at SUSE I tested my Tumbleweed install with the Kernel of the Day.

first did:  BOOT_IMAGE=/boot/vmlinuz-5.0.0-rc8-1.g4ddf057-default root=UUID=fce8b6dd-98d6-4b86-a5d9-2812f3c1e242 splash=silent resume=/dev/disk/by-uuid/c9f35ed5-bdbe-413a-801b-7df1c8a64145 quiet

and it booted with a screen

then did:   BOOT_IMAGE=/boot/vmlinuz-5.0.0-rc8-1.g4ddf057-default root=UUID=fce8b6dd-98d6-4b86-a5d9-2812f3c1e242 splash=silent resume=/dev/disk/by-uuid/c9f35ed5-bdbe-413a-801b-7df1c8a64145 quiet amdgpu.dc=1

and it also booted with a screen

so on this specifik hardware HP Notebook - 17-ca0710nd, Advanced Micro Devices, Inc. [AMD/ATI] Stoney [Radeon R2/R3/R4/R5 Graphics] it seems to be fixed
Comment 27 Dev Bazilio 2019-02-27 12:42:16 UTC
My RX550 is successfully booted up with 4.20 kernels and newer, but my OS freezes every minute for 30 secs if I open youtube or play game, and anything doesn't work upon freeze - I couldn't move mouse or press REISUB. Entire system is stuck. I downgraded kernel to 4.14 - and it works like a charm without lags/freezes/stucks. And it seems 4.14 doesn't have AMD DC (amdgpu.dc=0 doesn't work for me)
Comment 28 Bogomil Vasilev 2019-03-07 15:42:41 UTC
(In reply to Alex van Kaam from comment #26)
> hi
> 
> on request of the people over at SUSE I tested my Tumbleweed install with
> the Kernel of the Day.
> 
> first did:  BOOT_IMAGE=/boot/vmlinuz-5.0.0-rc8-1.g4ddf057-default
> root=UUID=fce8b6dd-98d6-4b86-a5d9-2812f3c1e242 splash=silent
> resume=/dev/disk/by-uuid/c9f35ed5-bdbe-413a-801b-7df1c8a64145 quiet
> 
> and it booted with a screen
> 
> then did:   BOOT_IMAGE=/boot/vmlinuz-5.0.0-rc8-1.g4ddf057-default
> root=UUID=fce8b6dd-98d6-4b86-a5d9-2812f3c1e242 splash=silent
> resume=/dev/disk/by-uuid/c9f35ed5-bdbe-413a-801b-7df1c8a64145 quiet
> amdgpu.dc=1
> 
> and it also booted with a screen
> 
> so on this specifik hardware HP Notebook - 17-ca0710nd, Advanced Micro
> Devices, Inc. [AMD/ATI] Stoney [Radeon R2/R3/R4/R5 Graphics] it seems to be
> fixed

Why do you set amdgpu.dc=1? Isn't this the default value anyway?
From what I understood, you tested exactly the same thing.
Comment 29 Dev Bazilio 2019-03-07 16:26:07 UTC
amdgpu.dc=1 set by default for all kernels since 4.17 and it seems that amdgpu.dc=0 is deprecated attribute as new Display core is replacement for old amdgpu code


5.0 version is works same as 4.20 with a lot of warnings and messages in dmesg
https://bugzilla.kernel.org/show_bug.cgi?id=201957
Comment 30 Alex van Kaam 2019-03-07 16:57:59 UTC
> 
> Why do you set amdgpu.dc=1? Isn't this the default value anyway?
> From what I understood, you tested exactly the same thing.

just to be sure, nothing more. I did not know for 100% it was the default now and is the default in the opensuse daily kernel.
Comment 31 Claude Heiland-Allen 2019-04-02 16:38:43 UTC
Created attachment 282101 [details]
dmesg logs after booting to X with displays connected to both DVI and HDMI

Good news: the bug only seems to affect the DVI output from my card.

I managed to connect another screen via an HDMI port and it works ok with amdgpu=1 (both screens have kernel messages mirrored until about 5 seconds into boot, when the DVI screen turns off - the HDMI screen stays on and I can log into X).

Attached are 7 dmesg logs, with amdgpu=1 unless specified.
Comment 32 Dev Bazilio 2019-09-20 11:22:43 UTC
All works perfectly in 5.3, no black screen and no any errors (Polaris RX540)
Comment 33 Sergey Kondakov 2019-11-05 14:07:45 UTC
This probably has reports from multiple separate bugs resulting in loss of output. It's easy to mix up with other bugs if you have only one monitor and your system is silently stuck on invisible login screen or if entire driver failed.

In my particular case, it's triggered by UEFI boot mode: when amdgpu is loaded it shuts down the output port that was used by UEFI BIOS during the boot, so I stuck with my secondary monitor only. It behaves as if monitor was yanked out the port. Reconnecting it physically does nothing. It works fine if CSM is used in motherboard but my new MB forces full UEFI, so I'm stuck with that.

Does anyone get "[drm] Cannot find any crtc or sizes" with multiple monitors ?
Comment 34 Bjoern Franke 2019-12-16 21:43:14 UTC
I'm getting this issue with only one monitor via HDMI connected. It was gone some kernel versions before and came back with 5.4.x it seems.
Comment 35 Claude Heiland-Allen 2019-12-16 23:52:47 UTC
Still getting this issue: with monitor connected via DVI, screen goes blank and monitor turns off a few seconds into boot (is fine before that, in motherboard power on display and grub and start of boot process).  With same monitor connected via HDMI and HDMI/DVI adaptor there are no issues.

Kernel versions tested today, with behaviour as above:
- 4.19.89
- 5.3.16
- 5.4.3 (partial test, forgot to test with DVI; HDMI works fine)
- 5.5-rc2
Comment 36 Adam 2020-02-15 14:42:23 UTC
I've run into this issue now when moving a Radeon RX 580 card into a Intel Z77 system with a 2500K. The same card has worked perfectly with DC enabled on AMD B350 and X470 motherboards. It is only this Asus P8Z77-V LX motherboard that has demonstrated the issue. I tested with both Legacy and UEFI boot modes with the same result.

The testing has been done with both Linux 5.3 and 5.4 kernels from Ubuntu.
Comment 37 Adam 2020-02-16 13:47:25 UTC
As several comments mention different behavior between the different connector types I found a spare DVI cable and tried connecting to the same monitor via that input and it worked! So once logged in I plugged in the HDMI cable and switched input and it worked just fine (monitor was glitchy at first but once I disabled DVI output in monitor configuration it worked perfectly). To confirm this was indeed working with the DC code path I tested audio over HDMI and it worked just fine (and does not work with DC disabled, as expected). So I rebooted with both the DVI and HDMI in and the output over HDMI worked all through boot. I then disconnected the DVI and rebooted and the HDMI continues to work so far. Unfortunately I don't have a displayport monitor around to test if that behaves as weirdly. Just to be clear, I had tried to make this monitor work for a couple weeks over HDMI and the only thing that worked was amdgpu.dc=0 until I plugged in the DVI connector so this was not a one off fail.

I forgot to mention before that when the HDMI output was not working with DC my Xorg logs also showed no monitor detected.

I can attach the two different Xorg logs if that helps?
Comment 38 babgozd 2020-02-16 21:12:14 UTC
(In reply to Adam from comment #37)
> As several comments mention different behavior between the different
> connector types I found a spare DVI cable and tried connecting to the same
> monitor via that input and it worked! So once logged in I plugged in the
> HDMI cable and switched input and it worked just fine (monitor was glitchy
> at first but once I disabled DVI output in monitor configuration it worked
> perfectly). To confirm this was indeed working with the DC code path I
> tested audio over HDMI and it worked just fine (and does not work with DC
> disabled, as expected). So I rebooted with both the DVI and HDMI in and the
> output over HDMI worked all through boot. I then disconnected the DVI and
> rebooted and the HDMI continues to work so far. Unfortunately I don't have a
> displayport monitor around to test if that behaves as weirdly. Just to be
> clear, I had tried to make this monitor work for a couple weeks over HDMI
> and the only thing that worked was amdgpu.dc=0 until I plugged in the DVI
> connector so this was not a one off fail.
> 
> I forgot to mention before that when the HDMI output was not working with DC
> my Xorg logs also showed no monitor detected.
> 
> I can attach the two different Xorg logs if that helps?
I am following this thread since it has created. My R9 380 with DVI-I output is connected to my VGA monitor with DVI-I male to VGA female adapter and I am getting black/blank screen while booting with amdgpu.dc=1 which is default since kernel 4.17. It is fine with amdgpu.dc=0. I can provide logs too if any kernel contributor wants to investigate the problem any further.
Comment 39 Meric07 2020-05-08 10:55:17 UTC
I experience the same problem with a R9 380X. Still can't boot into any distro with DC enabled. My monitor doesn't offer any other connection than VGA input, my GPU only offers DVI output, so i use a VGA to DVI adapter. It's disappointing this issue still continues after so many kernel revisions. I'll watch this thread hoping for good news.
Comment 40 Alex Deucher 2020-05-08 15:12:27 UTC
(In reply to Meric07 from comment #39)
> I experience the same problem with a R9 380X. Still can't boot into any
> distro with DC enabled. My monitor doesn't offer any other connection than
> VGA input, my GPU only offers DVI output, so i use a VGA to DVI adapter.
> It's disappointing this issue still continues after so many kernel
> revisions. I'll watch this thread hoping for good news.

I don't think this is related to the original report.  Does passing amdgpu.dc=0 on the kernel command line in grub fix the issue?
Comment 41 Meric07 2020-05-08 18:20:24 UTC
(In reply to Alex Deucher from comment #40)
> (In reply to Meric07 from comment #39)
> > I experience the same problem with a R9 380X. Still can't boot into any
> > distro with DC enabled. My monitor doesn't offer any other connection than
> > VGA input, my GPU only offers DVI output, so i use a VGA to DVI adapter.
> > It's disappointing this issue still continues after so many kernel
> > revisions. I'll watch this thread hoping for good news.
> 
> I don't think this is related to the original report.  Does passing
> amdgpu.dc=0 on the kernel command line in grub fix the issue?
Yes, with dc=0 the system starts up normally. I'm not sure if this is a fix or a workaround though.
Comment 42 babgozd 2020-05-30 19:22:27 UTC
(In reply to Meric07 from comment #41)
> (In reply to Alex Deucher from comment #40)
> > (In reply to Meric07 from comment #39)
> > > I experience the same problem with a R9 380X. Still can't boot into any
> > > distro with DC enabled. My monitor doesn't offer any other connection
> than
> > > VGA input, my GPU only offers DVI output, so i use a VGA to DVI adapter.
> > > It's disappointing this issue still continues after so many kernel
> > > revisions. I'll watch this thread hoping for good news.
> > 
> > I don't think this is related to the original report.  Does passing
> > amdgpu.dc=0 on the kernel command line in grub fix the issue?
> Yes, with dc=0 the system starts up normally. I'm not sure if this is a fix
> or a workaround though.

It has to be just a workaround. There is a problem with AMDGPU Display Code or something that utilizes it but since even console goes black, problem is something within kernel. Setting "amdgpu.dc=0" basically disable AMDGPU Display Code so we do not benefit from it.
Comment 43 Lukas Fink 2020-06-16 23:39:32 UTC
(In reply to babgozd from comment #38)
> I am following this thread since it has created. My R9 380 with DVI-I output
> is connected to my VGA monitor with DVI-I male to VGA female adapter and I
> am getting black/blank screen while booting with amdgpu.dc=1 which is
> default since kernel 4.17. It is fine with amdgpu.dc=0. I can provide logs
> too if any kernel contributor wants to investigate the problem any further.

To me it seems, as if the DVI-I port is somehow misdetected/misconfigured as a DVI-D port. With dc=0 I find the files "card1-DVI-I-1" and "card1-DVI-D-1" in "/sys/class/drm/card1". With dc=1 there are "card1-DVI-D-1" and "card1-DVI-D-2".

It appears to correctly negotiate resolution and refresh rate over DDC, but because it only outputs the digital signal, a display connected over VGA receives nothing and turns off.
Comment 44 Alex Deucher 2020-06-17 02:24:36 UTC
There is no support for analog displays in DC.
Comment 45 Sergey Kondakov 2020-06-17 03:11:16 UTC
(In reply to Alex Deucher from comment #44)
> There is no support for analog displays in DC.

Which was a horrible decision. Luckily, decent DP->VGA adapters actually work even with proper ≥1080p ≥85fps CRTs. But it still has some problems with DVI ports and/or HDMI->DVI adapters or certain monitors. Seems my issue with no output at all in UEFI mode was a separate one and has to do with BIOS's signing DRM nonsense. Hacked VBIOS works fine with UEFI… if you don't count just initializing sole DP port at boot… which has backup/special-purpose CRT connected and not real primary display in DVI.

But in either mode with dc=1 it just doesn't want to acknowledge my BENQ G2320HDB connected with a simple HDMI->DVI adapter, as if it doesn't exist, and there is no second DVI port. Maybe HDCP shenanigans ?

There is also another issue with amdgpu failing to initialize and hanging display output at boot, if 64-bit PCIe addressing ("above 4G decoding") is enabled, unless pcie=nocrs specified for kernel but that's a third issue and likely has to do with crappy BIOS of my new unlicensed LGA2011 motherboard (even though it works fine on Windows):
amdgpu: [powerplay] 
 failed to send message 254 ret is 0 
amdgpu: [powerplay] SMU load firmware failed
amdgpu: [powerplay] fw load failed
smu firmware loading failed
amdgpu 0000:03:00.0: amdgpu_device_ip_init failed
amdgpu 0000:03:00.0: Fatal error during GPU init
[drm] amdgpu: finishing device.
Comment 46 wevsty 2020-06-28 09:25:22 UTC
I have the same problem.

Kernel version 5.4.0-39-generic on ubuntu.
Graphics card: AMD RX580.
Motherboard: ASRock Z87.
Monitor: Compaq x22LED (Using HDMI to DVI-D adapter connected)

If you use the default configuration the startup will quickly black screen, if you use amdgpu.dc=0 it will display normally.

I'll post the demsg that provides when the dc is 0 and 1 to help diagnose the problem.
Comment 47 wevsty 2020-06-28 09:26:42 UTC
Created attachment 289905 [details]
5.4.0 amdgpu.dc=0 drm.debug=0xe
Comment 48 wevsty 2020-06-28 09:27:25 UTC
Created attachment 289907 [details]
5.4.0 amdgpu.dc=1 drm.debug=0xe
Comment 49 farshad 2021-04-06 07:51:47 UTC
Had the same problem 
on a Dell Latitude 5410 
with a Lexa Radeon E9171 MCM
and linux kernel 4.19.0.13 (Debian Buster),

Read it's still and issue with 4.20-rc5

*Now operational with a kernel 5.11*
default options.

The Lexa serie is in the RX540, RX550 550X et RX550X range,
(sold 80$ en 2017)

DRM was loading followed by 
ACPI error, field tmpb at bot offset exceed size of target buffer...
method parse/execution failed SB.PCIO.GFX0.ATRM, AE_AML_BUFFER_LIMIT
Error message was :
Error DC : number of connector is zero