572994bf18ff prevents system boot

[Chuck Lever III <chuck.lever@oracle.com>]

Hi-

After updating one of my test systems to v5.15-rc, I found that it
becomes unresponsive during the later part of the boot process. A
power-on reset is necessary to recover.

I bisected to this commit:

572994bf18ff ("drm/ast: Zero is missing in detect function")

Checking out v5.15-rc3 and reverting this commit enables the system
to boot again.

0b:00.0 VGA compatible controller: ASPEED Technology, Inc. ASPEED Graphics Family (rev 30) (prog-if 00 [VGA controller])
        DeviceName:  ASPEED Video AST2400
        Subsystem: Super Micro Computer Inc X10SRL-F
        Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Interrupt: pin A routed to IRQ 18
        Region 0: Memory at fa000000 (32-bit, non-prefetchable) [size=16M]
        Region 1: Memory at fb000000 (32-bit, non-prefetchable) [size=128K]
        Region 2: I/O ports at c000 [size=128]
        Expansion ROM at 000c0000 [virtual] [disabled] [size=128K]
        Capabilities: [40] Power Management version 3
                Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+)
                Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [50] MSI: Enable- Count=1/4 Maskable- 64bit+
                Address: 0000000000000000  Data: 0000
        Kernel driver in use: ast
        Kernel modules: ast

--
Chuck Lever