Panasonic DC-GH5 capture-tethered often results in 0 byte file size for 2nd triggered capture

[dustinkerstein]

When capturing with --capture-tethered I often see the 2nd file transfer with a 0 byte file size.

4.947475 debug_objectinfo            (2): ObjectInfo for '_1300143.JPG':
4.947482 debug_objectinfo            (2):   Object ID: 0x1220808f
4.947487 debug_objectinfo            (2):   StorageID: 0x00010001
4.947491 debug_objectinfo            (2):   ObjectFormat: 0x3801
4.947496 debug_objectinfo            (2):   ProtectionStatus: 0x0000
4.947501 debug_objectinfo            (2):   ObjectCompressedSize: 0

See here for the full debug. Note that when I trigger photos normally (ie. without being tethered) I never see 0 byte files.

Camera/Host setup:

• Writing to the Raspberry Pi 4b's /dev/shm ramdisk
• Panasonic DC-GH5 connected to USB3 port and verified at 5gbps bus speed
• Shutter speed - 1/40th
• Manual focus lens with no electrical contacts
• Lexar UHS-II 2000x 300MB/s 32GB SD card
• JPEG Fine output with file size ~6MB

Version Info:

gphoto2         2.5.28         gcc, popt(m), exif, no cdk, no aa, no jpeg, no readline
libgphoto2      2.5.30         standard camlibs (SKIPPING docupen lumix), gcc, no ltdl, EXIF
libgphoto2_port 0.12.1         iolibs: disk ptpip serial usb1 usbdiskdirect usbscsi, gcc, no ltdl, EXIF, USB, serial without locking

Let me know if you'd like any further info / debug. Thanks for the help!

[dustinkerstein]

Looks like this could be related to #488 and #526