Hello,

I'm facing probably a similar problem on this machine during resume after s2ram with linux 5.10.7 (see attached file "trace").

The error happens in drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_link_encoder.c:483 (see ^^^^-line):

unsigned int dcn10_get_dig_frontend(struct link_encoder *enc)
{
	struct dcn10_link_encoder *enc10 = TO_DCN10_LINK_ENC(enc);
	int32_t value;
	enum engine_id result;

	REG_GET(DIG_BE_CNTL, DIG_FE_SOURCE_SELECT, &value);

	switch (value) {
	case DCN10_DIG_FE_SOURCE_SELECT_DIGA:
		result = ENGINE_ID_DIGA;
		break;
	case DCN10_DIG_FE_SOURCE_SELECT_DIGB:
		result = ENGINE_ID_DIGB;
		break;
	case DCN10_DIG_FE_SOURCE_SELECT_DIGC:
		result = ENGINE_ID_DIGC;
		break;
	case DCN10_DIG_FE_SOURCE_SELECT_DIGD:
		result = ENGINE_ID_DIGD;
		break;
	case DCN10_DIG_FE_SOURCE_SELECT_DIGE:
		result = ENGINE_ID_DIGE;
		break;
	case DCN10_DIG_FE_SOURCE_SELECT_DIGF:
		result = ENGINE_ID_DIGF;
		break;
	case DCN10_DIG_FE_SOURCE_SELECT_DIGG:
		result = ENGINE_ID_DIGG;
		break;
	default:
		// invalid source select DIG
		ASSERT(false);
		result = ENGINE_ID_UNKNOWN;
		^^^^^^^^^^^^^^^^^^^^^^^^^^^
	}

	return result;
}


About the machine:
It's a notebook with two GPUs. AMD is the primary GPU - the secondary GPU (Nvidia) is unused (nouveau is not loaded at all - the proprietary driver isn't even installed)

05:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Picasso (rev c1) (prog-if 00 [VGA controller])
        Subsystem: ASUSTeK Computer Inc. Device 18f1
        Flags: bus master, fast devsel, latency 0, IRQ 24
        Memory at e0000000 (64-bit, prefetchable) [size=256M]
        Memory at f0000000 (64-bit, prefetchable) [size=2M]
        I/O ports at c000 [size=256]
        Memory at f7500000 (32-bit, non-prefetchable) [size=512K]
        Capabilities: [48] Vendor Specific Information: Len=08 <?>
        Capabilities: [50] Power Management version 3
        Capabilities: [64] Express Legacy Endpoint, MSI 00
        Capabilities: [a0] MSI: Enable- Count=1/4 Maskable- 64bit+
        Capabilities: [c0] MSI-X: Enable+ Count=3 Masked-
        Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
        Capabilities: [200] #15
        Capabilities: [270] #19
        Capabilities: [2a0] Access Control Services
        Capabilities: [2b0] Address Translation Service (ATS)
        Capabilities: [2c0] Page Request Interface (PRI)
        Capabilities: [2d0] Process Address Space ID (PASID)
        Capabilities: [320] Latency Tolerance Reporting
        Kernel driver in use: amdgpu
        Kernel modules: amdgpu

01:00.0 VGA compatible controller: NVIDIA Corporation TU117M [GeForce GTX 1650 Mobile / Max-Q] (rev a1) (prog-if 00 [VGA controller])
        Subsystem: ASUSTeK Computer Inc. Device 109f
        Flags: fast devsel, IRQ 255
        Memory at f6000000 (32-bit, non-prefetchable) [disabled] [size=16M]
        Memory at c0000000 (64-bit, prefetchable) [disabled] [size=256M]
        Memory at d0000000 (64-bit, prefetchable) [disabled] [size=32M]
        I/O ports at f000 [disabled] [size=128]
        Expansion ROM at f7000000 [disabled] [size=512K]
        Capabilities: [60] Power Management version 3
        Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
        Capabilities: [78] Express Legacy Endpoint, MSI 00
        Capabilities: [100] Virtual Channel
        Capabilities: [250] Latency Tolerance Reporting
        Capabilities: [258] L1 PM Substates
        Capabilities: [128] Power Budgeting <?>
        Capabilities: [420] Advanced Error Reporting
        Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024 <?>
        Capabilities: [900] #19
        Capabilities: [bb0] #15
        Kernel modules: nouveau

CPU: AMD Ryzen 7 3750H with Radeon Vega Mobile Gfx

Could you please fix this problem, too?
Please CC me for any answer because I'm not regularly reading the kernel mailing list.


Thanks
Andreas Hartmann