Add another unhappy 5770 user to this list.
I have just booted into HS, put the Mac to sleep and then woken it. This resulted in the black screen, but the up/down volume keys made a sound and the disk eject button worked. I tried typing in my lock-screen pass code blind, but after that there was nothing responding at all. So, I did a reboot, and have copied what was recorded in both the System Log and System Report. I'm no techie, so have probably copied stuff that has no bearing, but here it is in case someone can make light of it.
System Log
Sep 27 17:04:01 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.WebKit.Networking.DE715682-06BE-4F15-ACD7-C50EDEEB9266[548]): Service exited with abnormal code: 1
Sep 27 17:04:02 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.imfoundation.IMRemoteURLConnectionAgent): Unknown key for integer: _DirtyJetsamMemoryLimit
Sep 27 17:04:03 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.rootless.init): Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
Sep 27 17:04:05 Matthews-Pro GarageBandExtension[554]: BUG in libdispatch client: dispatch_mig_server: mach_msg() failed (ipc/send) msg too small - 0x10000008
Sep 27 17:04:05 Matthews-Pro iTunesStorageExtension[559]: BUG in libdispatch client: dispatch_mig_server: mach_msg() failed (ipc/send) invalid data - 0x10000002
Sep 27 17:04:12 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.CloudDocsDaemon.StorageManagement[557]): Service exited due to signal: Killed: 9 sent by CloudDocsStorageManagement[557]
Sep 27 17:04:12 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.STMExtension.Trash[553]): Service exited due to signal: Killed: 9 sent by Trash[553]
Sep 27 17:04:12 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.STMExtension.Applications[549]): Service exited due to signal: Killed: 9 sent by Applications[549]
Sep 27 17:04:12 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.STMExtension.iOSFiles[558]): Service exited due to signal: Killed: 9 sent by iOSFilesExtension[558]
Sep 27 17:04:12 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.messages.StorageManagementExtension[552]): Service exited due to signal: Killed: 9 sent by Messages Storage Management Exte[552]
Sep 27 17:04:12 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.WebKit.Networking.77B13238-505E-48AE-8367-EC545BB674AE[570]): Service exited with abnormal code: 1
Sep 27 17:04:17 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.STMExtension.OtherUsers[551]): Service did not exit 5 seconds after SIGTERM. Sending SIGKILL.
Sep 27 17:04:17 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.iTunesStorageExtension[559]): Service did not exit 5 seconds after SIGTERM. Sending SIGKILL.
Sep 27 17:04:17 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.Photos.StorageManagementExtension[550]): Service did not exit 5 seconds after SIGTERM. Sending SIGKILL.
Sep 27 17:04:20 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.imfoundation.IMRemoteURLConnectionAgent): Unknown key for integer: _DirtyJetsamMemoryLimit
Sep 27 17:04:37 Matthews-Pro timed[76]: settimeofday({0x59cbcc15,0x20d25}) == 0
Sep 27 17:04:37 Matthews-Pro keyboardservicesd[486]: assertion failed: 17A365: libxpc.dylib + 71201 [E7C5DB12-6D0E-3D1E-A743-F750DF112F5F]: 0x89
Sep 27 17:04:42 Matthews-Pro systemmigrationd[561]: BUG in libdispatch client: dispatch_mig_server: mach_msg() failed (ipc/send) msg too small - 0x10000008
Sep 27 17:05:43 Matthews-Pro timed[76]: settimeofday({0x59cbcc57,0x2031a}) == 0
Sep 27 17:05:53 Matthews-Pro com.apple.xpc.launchd[1] (com.apple.OSDUIHelper): Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
System Report
Wed Sep 27 17:05:53 2017
Event: GPU Reset
Date/Time: Wed Sep 27 17:05:53 2017
Application:
Path:
Tailspin: /Library/Logs/DiagnosticReports/gpuRestart2017-09-27-170553.tailspin
GPUSubmission Trace ID: 0
OS Version: Mac OS X Version 10.13 (Build 17A365)
Graphics Hardware: ATI Radeon HD 5770
Signature: 0
Report Data:
GPURestartReportStart
------------------------
Hung Channels: PM4
------------------------
[00] AccelChannel: PM4
Pending Command from : UnknownCtx
PendingCommandTimestamp: 0x00011ea1, TotalDWords: 0x00000415, GART Offset=0x0000000040080000, stamp_idx=0, estamp=0x00011ea1
PendingCommandStart:
PendingCommandEnd
------------------------
[00] PM4 HWChannel : Enabled, NotIdle
LastReadTimestamp : 0x00011ea0
NextSubmitTimestamp : 0x00011ea1
------------------------
GPU HangFlags 0x00000006: AsicHangState 0x00000006, AsicResetRequirement 0x00000002
IndividualEngineHang: 0
NonEngineBlockHang : 1
FenceNotRetired : 1
PerEngineReset : 0
FullAsicReset : 1
HangEngineBitmap : 0x00000000
------------------------
AMDJuniperGraphicsAccelerator PCIe Device: [2:0:0] State: DISABLED
Configuration: deviceBits: 0x001168b8, capabilityBits: 0x30940100
TotalVideoRAMBytes: 0x0000000040000000 (1073741824)
------------------------
[00] PM4 Engine : Enabled, NotIdle
[00] PM4 Channel: Enabled, NotIdle, lastReadTimestamp 0x00011ea0, nextSubmitTimestamp 0x00011ea1
------------------------
[01] SDMA Engine : Disabled, Idle
[01] DMA Channel: Disabled, Idle, lastReadTimestamp 0x000007e3, nextSubmitTimestamp 0x000007e4
------------------------
[03] UVD Engine : Disabled, Idle
[02] UVD Channel: Disabled, Idle, lastReadTimestamp 0x00000000, nextSubmitTimestamp 0x00000001