Camera detected but unable to capture image

[camoverride]

Describe the bug

>>> gphoto2 --capture-image

*** Error ***
An error occurred in the io-library ('I/O problem'): No error description available
ERROR: Could not capture image.
ERROR: Could not capture.

*** Error ***
An error occurred in the io-library ('I/O problem'): No error description available

additionally:

>>> sudo gphoto2 --capture-image

*** Error ***
PTP General Error

*** Error ***
An error occurred in the io-library ('Unspecified error'): No error description available
ERROR: Could not capture image.
ERROR: Could not capture.

*** Error ***
PTP General Error

*** Error ***
An error occurred in the io-library ('Unspecified error'): No error description available

Name the camera

>>> gphoto2 --auto-detect

Model                          Port
----------------------------------------------------------
Canon EOS 30D (PTP mode)       usb:001,003

libgphoto2 and gphoto2 version output of: gphoto2 --version

This version of gphoto2 is using the following software versions and options:
gphoto2         2.5.28.1       gcc, popt(m), exif, no cdk, no aa, jpeg, no readline
libgphoto2      2.5.27         standard camlibs, gcc, ltdl, EXIF
libgphoto2_port 0.12.0         iolibs: disk ptpip serial usb1 usbdiskdirect usbscsi, gcc, ltdl, EXIF, USB, serial without locking

To Reproduce Steps to reproduce the behavior:

If its a camera misbehavior, attach debug output using --debug --debug-logfile=debug.log (if considered useful).

[msmeissn]

a debug logfile would be needed to help debug this.

[andi34]

Similar error message seen on EOS 300D and 350D, was about missing permission/udev rule.

SUBSYSTEM=="usb", ATTRS{idVendor}=="04a9", ATTRS{idProduct}=="3099", GROUP="plugdev", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="04a9", ATTRS{idProduct}=="3084", GROUP="plugdev", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="04a9", ATTRS{idProduct}=="30ee", GROUP="plugdev", MODE="0666"

EOS 300D

https://devicehunt.com/view/type/usb/vendor/04A9/device/3099 https://devicehunt.com/view/type/usb/vendor/04A9/device/3084

EOS 350D

https://devicehunt.com/view/type/usb/vendor/04A9/device/30EE