Using Module Parameters: A Last Resort


If a module fails to load, you do not get an error message, but the installer asks again how to locate the missing piece of hardware and continues to offer you the same list of drivers. If you are sure about the type of hardware you possess and yet your driver is failing to load, you might need to supply extra information to the driver to get it to load correctly. Unfortunately, the list of values needed by each driver can be found only in the source code of the Linux kernel itself or from the driver's author (or manufacturer). You can download the source code of the Linux kernel from the anonymous FTP site ftp.kernel.org. Because navigating the Linux kernel source requires some experience in dealing with programming in the C language, module parameters are best used by experienced users or those with previous Linux experience.

To supply parameters to a module, use the Tab key to highlight the Specify Optional Module Arguments option and then press the spacebar to select it; an asterisk appears in the selection box, as shown in Figure A.4.

Figure A.4. If the driver doesn't load the first time, try again, but choose to specify module arguments.


When you attempt to load a driver after selecting that you want to specify module arguments, the Enter Module Parameters screen is displayed before the driver is loaded. In this screen, you can enter various types of configuration data, as shown in Figure A.5.

Figure A.5. You can configure the device driver in the Enter Module Parameters screen if you are familiar with your hardware.


The set of options that can be configured varies from device to device, but generally some indication is provided for how to proceed, though it might at first seem obtuse. The Enter Module Parameters screen displays anywhere from one to several input lines, each of which accepts additional information about the module or driver. For example, some SCSI drivers might ask you to supply an input/output base address (ioport), interrupt request line (irq), and host adapter SCSI ID (host scsiid) in a specific format. Follow the cues given on the Enter Module Parameters screen to enter the information for your hardware.

In some cases, the module's request for information is more explicit: A module might ask only for an IRQ, a base address, or a revision level for your hardware. If in doubt, feel free to experiment with values to try to get your hardware working. Obviously, you must be reasonably familiar with PC hardware in general, with your own hardware in particular, and with the conventions in use in Linux and the C programming language to be able to configure module parameters effectively during the install process. Regrettably, every driver is different, so the information you must provide and the format in which it should be provided varies from driver to driver (and from manufacturer to manufacturer, if you have manufacturer-supplied driver disks for Fedora Core 4 or for Fedora Core 4). Try to follow the visual cues and supplied values for each driver as guidelines. In the end, it is nearly always easier for inexperienced users to replace an undetected hardware item than to try to load a driver manually in this fashion.



    SAMS Teach Yourself Red Hat(r) Fedora(tm) 4 Linux(r) All in One
    Cisco ASA and PIX Firewall Handbook
    ISBN: N/A
    EAN: 2147483647
    Year: 2006
    Pages: 311
    Authors: David Hucaby

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