Bug#1022147: Problem also with 149-2 and Kernel-Option amdgpu.dc=0

[debian@pc-vor-ort.net]

We had have Problems with 5.10.0.19 (149-1) and all AMD-Computers with 
onboard graphics.

Update 149-2 had solved on most computers, but this computer has shows 
blankscreen a boot...

I have remove boot-option amdgpu.dc=1, since this change 149-2 works.

What has changed between 5.10.0.18 and 5.10.0.19-149-2 at usage of 
amdgpu.dc=0? Can anyone explain?

Here my lspci (stripped):

00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 
Root Complex
    Subsystem: ASUSTeK Computer Inc. PRIME B450M-A Motherboard
    Flags: fast devsel

00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Raven/Raven2 IOMMU
    Subsystem: ASUSTeK Computer Inc. PRIME B450M-A Motherboard
    Flags: bus master, fast devsel, latency 0, IRQ 25
    Capabilities: [40] Secure device <?>
    Capabilities: [64] MSI: Enable+ Count=1/4 Maskable- 64bit+
    Capabilities: [74] HyperTransport: MSI Mapping Enable+ Fixed+

00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller 
(rev 61)
    Subsystem: ASUSTeK Computer Inc. PRIME Motherboard
    Flags: 66MHz, medium devsel, IOMMU group 6
    Kernel driver in use: piix4_smbus
    Kernel modules: i2c_piix4, sp5100_tco

00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge 
(rev 51)
    Subsystem: ASUSTeK Computer Inc. PRIME B450M-A Motherboard
    Flags: bus master, 66MHz, medium devsel, latency 0, IOMMU group 6


01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. 
[AMD/ATI] Lexa PRO [Radeon 540/540X/550/550X / RX 540X/550/550X] (rev 
c7) (prog-if 00 [VGA controller])
    Subsystem: Hewlett-Packard Company Lexa PRO [Radeon 
540/540X/550/550X / RX 540X/550/550X]
    Flags: bus master, fast devsel, latency 0, IRQ 107, IOMMU group 8
    Memory at e0000000 (64-bit, prefetchable) [size=256M]
    Memory at f0000000 (64-bit, prefetchable) [size=2M]
    I/O ports at e000 [size=256]
    Memory at fcf00000 (32-bit, non-prefetchable) [size=256K]
    Expansion ROM at fcf40000 [disabled] [size=128K]
    Capabilities: [48] Vendor Specific Information: Len=08 <?>
    Capabilities: [50] Power Management version 3
    Capabilities: [58] Express Legacy Endpoint, MSI 00
    Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 
Len=010 <?>
    Capabilities: [150] Advanced Error Reporting
    Capabilities: [200] Physical Resizable BAR
    Capabilities: [270] Secondary PCI Express
    Capabilities: [2b0] Address Translation Service (ATS)
    Capabilities: [2c0] Page Request Interface (PRI)
    Capabilities: [2d0] Process Address Space ID (PASID)
    Capabilities: [320] Latency Tolerance Reporting
    Capabilities: [328] Alternative Routing-ID Interpretation (ARI)
    Capabilities: [370] L1 PM Substates
    Kernel driver in use: amdgpu
    Kernel modules: amdgpu

02:00.0 USB controller: Advanced Micro Devices, Inc. [AMD] 300 Series 
Chipset USB 3.1 xHCI Controller (rev 02) (prog-if 30 [XHCI])
    Subsystem: ASMedia Technology Inc. 300 Series Chipset USB 3.1 xHCI 
Controller
    Flags: bus master, fast devsel, latency 0, IRQ 33, IOMMU group 9
    Memory at fcca0000 (64-bit, non-prefetchable) [size=32K]
    Capabilities: [50] MSI: Enable- Count=1/8 Maskable- 64bit+
    Capabilities: [68] MSI-X: Enable+ Count=8 Masked-
    Capabilities: [78] Power Management version 3
    Capabilities: [80] Express Legacy Endpoint, MSI 00
    Capabilities: [100] Advanced Error Reporting
    Capabilities: [200] Secondary PCI Express
    Capabilities: [300] Latency Tolerance Reporting
    Capabilities: [400] L1 PM Substates
    Kernel driver in use: xhci_hcd
    Kernel modules: xhci_pci


CPU: AMD Ryzen 5 3400G with Radeon Vega Graphics
GPU: Radeon 540/540X/550/550X / RX 540X/550/550X


Thank you!