libcam.so

Runs on:

QNX Neutrino

Options:

The driver is one of the block device (devb-*) drivers. The cam options control the driver's interface to libcam.so. These options must follow the cam keyword, and can be any of the ones described below. Not all options apply to all block device drivers.

async

Perform CPU cache invalidation after an I/O operation in a thread that's separate from the one that's notifying the upper layer. In some cases, and on some boards, this can provide a performance boost.

bounce=size

Specify the size of the driver's “bounce” buffer. The size argument can include a case-insensitve suffix that indicates the units: B (bytes; the default), K (kilobytes), M (megabytes), or P (pages). The bounce buffer is used if a specific piece of hardware can't directly access io-blk block cache buffers. The most common example is chips that don't support scatter-gather. The default is 32 KB.

cache[=on|off]

Specify to perform cache invalidation or cache flushes on the buffers. Map the bounce buffer as PROT_NOCACHE (cache=off) or not (cache or cache=on). The default is on.

lun=mask

Enable Logical Unit Number (LUN) scan for the devices specified in mask. The mask is a hexadecimal bitmask specifying which IDs to scan for; the default is 0x00.

maxio=wr:rd

Set the maximum number of I/O write blocks (wr) and read blocks (rd). The default for both settings is 4096, but the maximum supported number is limited by the device.

noio

Completely remove the IO ability. Neither ThreadCtl(_NTO_TCTL_IO, ...) nor ThreadCtl(_NTO_TCTL_IO_PRIV, ...) will be called.

nopriv

Don't call ThreadCtl(_NTO_TCTL_IO_PRIV, ...).

pnp

Enable CAM plug and play (i.e., don't exit at startup when no devices are found). The default is off.

resmgr=m:l:h:d

Enable the /dev/camX/XXX interface and set the maximum (m), low (l), high (h), and devno (d) thread-pool parameters. This option provides an interface to send CAM SCSI passthrough requests that bypass the io-blk media relearn.

The default is 5:1:2:-1.

retries=num

Specify the number of times to retry an operation before indicating to the filesystem that an I/O error occurred. The default is 10.

smmu[=0|1|off|on]

(QNX Neutrino 7.0.4 or later) Specify whether or not support for the system memory management unit (IOMMU/SMMU) manager (smmuman) is required. If you don't provide a value for this option, support is enabled, but you can explicitly enable it with the 1 or on setting, or disable it with 0 or off. For more information, see the SMMUMAN User's Guide.

The default is off; if you enable this option and smmuman isn't running, the driver exits.

timeout=g1:g2:g3:rw

Set the group command and read/write timeouts, in seconds. The default values are obtained from the Timeout & Protect mode page if it's supported; otherwise they're 60:90:10:10.

The timeout values are based on the group of the SCSI command being issued. The command and group are defined in the SCSI specification. In most cases, you just want to use the default values for g1, g2, and g3 and change only rw.

user=UID:GID

Operate as the specified user and group IDs. The driver retains the necessary process-manager abilities.

verbose

Increase the verbosity of the low-level hardware driver.

Description:

The libcam.so shared object provides support for common access methods for block device (devb-*) drivers.