Video "chopped" bug in latest alpha and r20.04

[dinoboy197]

Platform	Branch	Hash	CIDL
Ubuntu 18.04	r20.04	046d94d4bf7b51418a82bdc90e25206c0a62fc25	No
Ubuntu 18.04	alpha	ab9d4762e0726a8cd9ca3e0f63213c1400094a0a	No
Ubuntu 18.04	alpha	971d6149a5bff446b35a97a2bfa977aa0d08ee3e	No

(each of these shas above have the issue reported below)

Description of the Issue

Sha ab9d4762e0726a8cd9ca3e0f63213c1400094a0a introduced some video mis-rendering (what I can only describe as "chopped") about 50% of the time when I run a ROM. The game functions properly, but the video is chopped up across the screen. What's peculiar is that the chop only appears partway through the start screen of the ROM: the Dreamcast logo shows up ok, the ROM intro logo shows up ok, then about 10 seconds in, the video spontaneously "chops" without any interaction from me. See the screenshots below to see what this looks like.

I've tested this in Ecco the Dolphin / Defender of the Future on x86_64.

Debugging Steps Tested

• Compile using previous working sha (1525af6f0cebf60990fee38c31f4d7588f46e0cf)
• Running ROM works properly - video is not broken
• Compile using broken sha (ab9d4762e0726a8cd9ca3e0f63213c1400094a0a)
• Running ROM works incorrectly - video broken on ~50% of runs

I'm happy to do more debugging on my end to help identify the problem. However, using git bisect and repeated testing isolated commit ab9d4762e0726a8cd9ca3e0f63213c1400094a0a which introduced the issue.

Logs Gathered

Config dir is: /home/traack/.reicast/
Data dir is:   /home/traack/.reicast/
Personality: 00000000
Updated personality: 00000000
Linux paging: 4096 00001000 00000FFF
Virtual cfg config:image=/home/traack/Games/ecco-the-dolphin-defender-of-the-future/Ecco the Dolphin - Defender of the Future (USA) (En,Fr,De,Es).gdi

GLX: Found 18 matching FB configs.
GLX: Chosen visual ID = 0x21
evdev: Opened device 'Sony Interactive Entertainment Wireless Controller' using custom mapping 'Sony Interactive Entertainment Wireless Controller mapping'
evdev: Opened device 'Sony Computer Entertainment Wireless Controller' using default mapping 'Generic Controller'
Screen DPI is 96, size 0 x 0. Scaling by 1.00
CreateContext
GLX: init OK
OpenGL version: 4.5 (Core Profile) Mesa 19.2.8
CreateContext Done
CreateFontsTexture
Initializing audio backend "pulse" (PulseAudio)...
Info: nvmem is enabled, with addr space of size 512MB
Info: p_sh4rcb: 0x7f42876f0000 virt_ram_base: 0x7f428f7f0000
Loaded /home/traack/.reicast/data/dc_boot.bin as bootrom

Loaded /home/traack/.reicast/data/dc_nvmem.bin as nvram

RendIF: renderer (auto): main: gl41 fallback: gles
Per-pixel sorting enabled
chd: chd_open failed for file /home/traack/Games/ecco-the-dolphin-defender-of-the-future/Ecco the Dolphin - Defender of the Future (USA) (En,Fr,De,Es).gdi: 5

GDI : 5 tracks
file[1] "Ecco the Dolphin - Defender of the Future (USA) (En,Fr,De,Es) (Track 1).bin": FAD:0, CTRL:4, SSIZE:2352, OFFSET:0
file[2] "Ecco the Dolphin - Defender of the Future (USA) (En,Fr,De,Es) (Track 2).bin": FAD:526, CTRL:0, SSIZE:2352, OFFSET:0
file[3] "Ecco the Dolphin - Defender of the Future (USA) (En,Fr,De,Es) (Track 3).bin": FAD:45000, CTRL:4, SSIZE:2352, OFFSET:0
file[4] "Ecco the Dolphin - Defender of the Future (USA) (En,Fr,De,Es) (Track 4).bin": FAD:85996, CTRL:0, SSIZE:2352, OFFSET:0
file[5] "Ecco the Dolphin - Defender of the Future (USA) (En,Fr,De,Es) (Track 5).bin": FAD:89948, CTRL:4, SSIZE:2352, OFFSET:0
gdrom: Opened image "/home/traack/Games/ecco-the-dolphin-defender-of-the-future/Ecco the Dolphin - Defender of the Future (USA) (En,Fr,De,Es).gdi"
Game ID is [MK-51033]
Sh4 Reset
recSh4 Init
Using MCPU Recompiler
Using SCPU Interpreter
Using DSP Interpreter
cntx // fpcb offset: -135266304 // pc offset: -184 // pc A0000000
recSh4:Dynarec Cache clear at 8C0000DE
Invalid GD-DMA start, SB_GDEN=0.Ingoring it.
VREG = 03 ARMRST 00
VREG = 03 ARMRST 01
VREG = 03 ARMRST 00
Invalid GD-DMA start, SB_GDEN=0.Ingoring it.
VREG = 03 ARMRST 00
VREG = 03 ARMRST 01
VREG = 03 ARMRST 01
VREG = 03 ARMRST 00
Texture cache cleared
RendIF: renderer (auto): main: gl41 fallback: gles
Per-pixel sorting enabled
recSh4:Dynarec Cache clear at AC0082FE
VREG = 03 ARMRST 00
recSh4:Dynarec Cache clear at AC00FFFE
VREG = 03 ARMRST 01
VREG = 03 ARMRST 00
Saved /home/traack/.reicast/data/dc_nvmem.bin as nvmem

Screenshots

Good (sha 1525af6f0cebf60990fee38c31f4d7588f46e0cf):

Bad (sha ab9d4762e0726a8cd9ca3e0f63213c1400094a0a):

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[clort81]

I get a similar bug with OpenGL backend, with both my games. Git master latest (today, 2020-08-26). Aarch64 CFLAGS=-march=native -mtune=cortex-a57 -ftree-vectorize -funsafe-math-optimizations -Os render problem goes away if i resize the window. Then it reappears on a scene change.

Render problem does not happen for me with gles backend.

I managed to make it go away once by selecting texture size 3 and resizing the window a few times.

[skmp]

Peculiar bug. Which board are you using?

On Wed, 26 Aug 2020, 19:38 clort81, notifications@github.com wrote:

[image: reicastbug1] https://user-images.githubusercontent.com/51511737/91331448-11216500-e7cb-11ea-8424-7e9cfe4ba783.png I get a similar bug with OpenGL backend, with both my games. Git master latest (today, 2020-08-26). Aarch64, armv8 render problem goes away if i resize the window. Then it reappears on a scene change.

Render problem does not happen for me with gles backend.

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[clort81]

Peculiar bug. Which board are you using?

Nvidia Jetson Nano server glx vendor string: NVIDIA Corporation server glx version string: 1.4

[dinoboy197]

For me, I have an Intel HD Graphics 620 (KBL GT2)

[biggestsonicfan]

Facing similar issues, causing the BIOS to not be displayed properly to set time. Compiled as of 2712a007b2ef739882ce0fb0076aedde3e27e393. OS: OpenSUSE Tumbleweed. GFX: Nvidia GeForce RTX 2060.

This appears to affect the VMU as well?