| .. -*- coding: utf-8; mode: rst -*- |
| |
| .. _gen_errors: |
| |
| ******************* |
| Generic Error Codes |
| ******************* |
| |
| |
| .. _gen-errors: |
| |
| .. flat-table:: Generic error codes |
| :header-rows: 0 |
| :stub-columns: 0 |
| :widths: 1 16 |
| |
| |
| - .. row 1 |
| |
| - ``EAGAIN`` (aka ``EWOULDBLOCK``) |
| |
| - The ioctl can't be handled because the device is in state where it |
| can't perform it. This could happen for example in case where |
| device is sleeping and ioctl is performed to query statistics. It |
| is also returned when the ioctl would need to wait for an event, |
| but the device was opened in non-blocking mode. |
| |
| - .. row 2 |
| |
| - ``EBADF`` |
| |
| - The file descriptor is not a valid. |
| |
| - .. row 3 |
| |
| - ``EBUSY`` |
| |
| - The ioctl can't be handled because the device is busy. This is |
| typically return while device is streaming, and an ioctl tried to |
| change something that would affect the stream, or would require |
| the usage of a hardware resource that was already allocated. The |
| ioctl must not be retried without performing another action to fix |
| the problem first (typically: stop the stream before retrying). |
| |
| - .. row 4 |
| |
| - ``EFAULT`` |
| |
| - There was a failure while copying data from/to userspace, probably |
| caused by an invalid pointer reference. |
| |
| - .. row 5 |
| |
| - ``EINVAL`` |
| |
| - One or more of the ioctl parameters are invalid or out of the |
| allowed range. This is a widely used error code. See the |
| individual ioctl requests for specific causes. |
| |
| - .. row 6 |
| |
| - ``ENODEV`` |
| |
| - Device not found or was removed. |
| |
| - .. row 7 |
| |
| - ``ENOMEM`` |
| |
| - There's not enough memory to handle the desired operation. |
| |
| - .. row 8 |
| |
| - ``ENOTTY`` |
| |
| - The ioctl is not supported by the driver, actually meaning that |
| the required functionality is not available, or the file |
| descriptor is not for a media device. |
| |
| - .. row 9 |
| |
| - ``ENOSPC`` |
| |
| - On USB devices, the stream ioctl's can return this error, meaning |
| that this request would overcommit the usb bandwidth reserved for |
| periodic transfers (up to 80% of the USB bandwidth). |
| |
| - .. row 10 |
| |
| - ``EPERM`` |
| |
| - Permission denied. Can be returned if the device needs write |
| permission, or some special capabilities is needed (e. g. root) |
| |
| .. note:: |
| |
| #. This list is not exaustive; ioctls may return other error codes. |
| Since errors may have side effects such as a driver reset, |
| applications should abort on unexpected errors, or otherwise |
| assume that the device is in a bad state. |
| |
| #. Request-specific error codes are listed in the individual |
| requests descriptions. |