Fortunately, most notebook manufacturers make it clear what video hardware they use. Ads for notebook computers typically include this information. Because the video support is integrated into the motherboard, the ads usually specify the video chipset that's in use. This is precisely what you need to know to locate a Linux driver, as described in Chapter 12, "Video Cards," and Appendix A, "Linux Device Drivers."
Sound chipsets are not always advertised quite as clearly as are video chipsets. Many manufacturers merely report that their notebooks have "SoundBlaster-compatible" sound, or they trumpet the manufacturer of the speakers, but don't mention who makes the sound chipset in use. In some cases the sound chipset is integrated into the motherboard chipset, and isn't well known to consumers. Many notebook computers sold in 2000 that use VIA chipsets, for instance, incorporate sound support from the VIA 82c686a, which is incorporated into some of VIA's recent motherboard chipsets.
In the case of both video and audio chipsets, you can usually find what the computer uses if you can access the computer when it's running Windows. To do so, open the System item in the Windows Control Panel, as shown in Figure 23.3. Click the Device Manager tab and then click the plus signs next to the Display adapters and Sound, video and game controllers items to reveal the video and audio chipsets used by the computer. In the case of the computer used to create Figure 23.3, the display adapter is a Trident CyberBlade i7, and the audio support comes from a VIA PCI audio controller.
Of course, if you want to find what hardware a notebook computer uses before you buy it, this method requires that you have access to the computer. Most local computer stores run display samples of notebook computers, so you can usually check the hardware before you buy. This
might not be possible for mail-order hardware, however. In this case, you might need to rely on the sales staff or some other resource. The Linux on Laptops Web page (http://www.cs.utexas.edu/users/kharker/linux-laptop/) is particularly useful in this respect. This Web page includes links to a large number of descriptions of Linux systems run on a wide variety of notebook computers. Many of these individual pages include links to the XF86Config files that the maintainers use. You can then download these files and use them yourself if you buy the same or a similar computer, thus saving you some time and effort configuring XFree86.
The Device Manager tab in the Windows System Properties dialog box can reveal the chipsets used by a notebook's audio and video hardware.
The Device Manager tab in the Windows System Properties dialog box can reveal the chipsets used by a notebook's audio and video hardware.
If you buy a new notebook that's not listed on one of these pages, you can do others a great favor by putting together a Web page describing your experiences and submitting it for inclusion on the Linux on Laptops page. Even a brief description stating that the computer works, and specifying your distribution, can be helpful.
When you know what chipsets a notebook computer uses for audio and video features, you can go looking for support for those chipsets. Chapters 10, "Sound Cards" and 12 can help you in this respect, as can Appendix A. In brief, though, you should check several Web sites and other resources for information:
• The Linux on Laptops Web page If the computer you're considering is listed on this page, you can generally find the information you need there.
• The Linux kernel configuration options Check the Linux kernel sound configuration options for standard support for your sound hardware.
• The Shareware OSS site Check http://www.4front-tech.com for information on commercial Linux sound drivers.
• The ALSA site Check http://www.alsa-project.org for information on the Advanced Linux Sound Architecture (ALSA) drivers.
• The XFree86 site Check http://www.xfree86.org for information on video support in XFree86. You might need to dig a bit on this site to find the information you require.
• The SuSE site SuSE (http://www.suse.com) contributes a lot to the XFree86 project, and often makes early versions of its XFree86 drivers available from its own site.
• The Accelerated-X site Accelerated-X, from Xi Graphics (http://www.xig.com), is a commercial alternative to XFree86.
• The Metro-X site Metro-X, from MetroLink (http://www.metrolink.com), is another commercial alternative to XFree86.
If you think it's likely that you can make a notebook's hardware work under Linux, but you're not positive you' ll succeed, you might still consider buying the computer. I recommend doing so only from a store with a good return policy, however. If you think you might need to use software with which you're not familiar, you might want to try that software on a desktop system, if possible, before buying the notebook. For instance, if your target notebook's sound chipset is supported by ALSA but not by the standard kernel drivers, you might want to try ALSA on another system, simply to familiarize yourself with it.
If your video chipset doesn't work under XFree86, you might still be able to use the computer in text mode. To use X programs, you'll need to link the computer to a network and use an X server running on another computer. That's not very convenient for a notebook, but it might be acceptable in a pinch.
If your audio chipset doesn't work under Linux, your options are somewhat broader, although still not good. Two possibilities are
• USB speakers These devices don't work through a standard sound card; instead, the sound card functions are included in the speakers themselves. You'll need to lug the speakers around with you wherever you go, or at least wherever you want sound support. You'll also need to use a 2.3.x or later kernel, or apply a back-port of the 2.3.x USB support to a 2.2.x kernel.
• PC Card sound card There are a small number of PC Card sound cards on the market. Most of these aren't well supported in Linux, however. For the latest information, check http://pcmcia.sourceforge.org/ftp/SUPPORTED.CARDS, which has links to information on supported PC Cards and projects to add new support. As with USB speakers, you'll need to carry around a set of conventional external speakers.
Many notebook computers include 1/8-inch jacks for speakers or headphones. Therefore, if your internal sound card works fine but you don't like the quality of speakers, you can use separate speakers or headphones. If you want portable speakers, you should be sure to get a model that supports operation on battery power, not just wall power.
Most input/output devices on notebook computers function much like their counterparts on desktop systems. A few comments are in order concerning specific devices, however:
• Ethernet Most notebook computers don't come with Ethernet built in. If you have a built-in Ethernet adapter, be sure it's adequate to your needs. I don't recommend buying a new notebook with built-in 10Mbps-only Ethernet, because 100Mbps speeds are now common. 10/100Mbps PC Card Ethernet adapters are common, and most are well supported in Linux. Check http://pcmcia.sourceforge.org/ftp/SUPPORTED.CARDS for details on specific models.
• Modem Most notebook computers today come with built-in modems. Unfortunately, most of these modems are software modems, many of which have no Linux support. What's worse, manufacturers do not generally advertise what modem chipsets they use, so you might have no clue what you're getting until you get the machine. If you can check the computer in a store, though, the Modem item in the Windows System Properties dialog box (refer to Figure 23.3) can be helpful. Check http://www. linmodems.org for information on software modems supported under Linux. Fortunately, PC Card modems are fairly common, and many of these are not software modems, so you can bypass a software modem if necessary. Be sure to check that the PC Card modem is supported in Linux, though, because some are software modems. You can also use a conventional external RS-232 serial modem or a Linux-supported USB modem. Most such devices require wall power, however, and they're bulkier than a PC Card modem.
• Keyboard and mouse Many notebook computers have a connector for PS/2-style keyboards and mice. You can also use USB devices on notebooks that are equipped with USB ports.
Notebook computers come with nicked-cadmium (NiCd), nickel metal hydride (NiMH), or lithium ion (Lion) batteries. As a general rule, NiCd batteries aren't used on modern notebooks, although you might find them on older models. Today's low-end models generally use NiMH batteries, whereas higher-end devices use Lion batteries. Lion batteries have higher capacities and suffer less from "memory" effects than do NiMH batteries.
There's little standardization in notebook computer batteries. A battery designed for one computer usually doesn't work in another. The main exceptions are in closely related computers from the same manufacturer.
In order to make batteries last as long as possible, most notebook computers implement a number of power-saving features. These features generally require communication between the hardware and the OS, and these features are often mediated by the BIOS. In Linux, they're implemented through the Advanced Power Management Daemon (APMD) package. The main APMD site for Linux is http://www.worldvisions.ca/~apenwarr/apmd/.
APMD requires a number of kernel options to function properly. You can activate these options in the General setup kernel configuration menu. Specific options you should consider include
• Advanced Power Management BIOS support This option is required. Without it, none of the other options are available.
• Enable PM at boot time Responding Y to this option enables most power management features. For instance, with this option enabled, the computer enters a power-saving sleep mode after a certain period of time.
• Make CPU Idle calls when idle This option can sometimes improve power savings slightly, by putting the CPU in a low-power mode if it's not been used for a while.
• Enable console blanking using APM If you regularly work in text mode, enable this option. It tells the system to blank the screen using APM BIOS calls, which can save battery power. If you don't enable this option, the screen goes blank, but it's still powered.
• Power off on shutdown Enable this option to have the computer power itself off when you shut it down with a command such as shutdown now -h. If you don't enable this option, you' ll need to use a manual power-off procedure, such as holding down the power switch for several seconds.
• RTC stores time in GMT If your notebook computer runs only Linux, you might want to store the system time as Greenwich Mean Time (GMT), which is the norm for UNIX systems. This procedure can cause glitches for power management, however, unless you enable this feature. If you choose to keep your hardware clock set to local time rather than GMT, you should set this option to N.
You might also need to use some of the other APM support options. Most of the remaining options are workarounds for bugs in various APM BIOSs, or are specialized options for rare situations.
Most Linux distributions come with a reasonable array of APM kernel options enabled. You therefore might not need to adjust these options. You should keep them in mind if and when you recompile your kernel, however.
You can manually query the APM configuration and issue APM commands using the apm program. Typing apm by itself produces a status report on the battery power, and typing apm -s puts the computer into suspend mode. In suspend mode, the computer consumes a small trickle of power, but the hard disk is powered down, the display is turned off, and the computer is generally dormant. You can wake the computer up again by pressing a key. Many computers include a special keystroke to enable suspend mode.
There are assorted X-based interfaces to APM functions, such as kapm (part of the KDE package) and xapm (which comes with some APMD packages). These interfaces provide a constant on-screen indication of the status of the battery. They can also sometimes suspend the system.
A notebook computer's hard disk accounts for a large part of its power consumption. You can use the hdparm utility to configure the hard disk to go into a low-power mode after a specified
APMD interfaces with the APM BIOS in order to provide APM services in Linux. Most Linux distributions ship with APMD configured to behave in a reasonable manner for both notebook and desktop systems, so you probably don't need to adjust your APMD configuration. If you do want to adjust the configuration, you can edit the timeout values in your computer's BIOS. How you enter the BIOS varies from one computer to another, so consult your documentation on this detail.
period of time, as described in Chapter 5. To summarize, you issue the hdparm command with the -S parameter in order to tell the system to power down the hard disk after a specified period. Table 23.1 summarizes the meanings of the -S parameter. As an example, hdparm -S 24 powers down the hard disk after 120 seconds (2 minutes).
Table 23.1 hdparm -S Options for Hard Disk Spindown Times
0 Energy-saving power-down disabled (drive is always fully active).
1-240 Multiples of 5 seconds; for instance, 6 means 30 seconds.
241-251 1-11 units of 30 minutes, for times ranging from 0.5-5.5 hours.
252 21 minutes.
253 Vendor-defined timeout value. 255 21 minutes and 15 seconds.
If you regularly use your notebook computer on battery power, it's important that you find a good hard disk power-down time for the way you use the system. If the period is too long, you'll waste battery power needlessly on keeping the hard disk spinning. If the period is too short, you'll end up being annoyed by the delays when the system awakens the hard disk. Because every individual's usage patterns are different, you'll have to experiment to find a good value.
Linux systems tend to access the hard disk more than Windows systems do. For instance, Linux maintains various log files (located in the /var/log directory tree), in which it stores important system events, such as logins, server activity, and so on. Even if you aren't actively using the computer, it's possible that various daemons and other background processes will perform disk accesses, thus resetting the clock on the hard disk power-down timer. Likewise, these events can cause the hard disk to spring to life even if you're not using the computer.
It's possible to run Linux on many modern (and not-so-modern) notebook computers. In fact, Linux can use advanced notebook-centric features such as APM and PC Cards, thus providing a good notebook experience. You must be unusually cautious when you choose a notebook computer, however, because it's difficult or impossible to replace certain critical hardware
components on a notebook computer. Prime among these is the video chipset, but the sound chipset is also quite difficult to replace. Therefore, before you buy a notebook, I strongly recommend that you check on hardware compatibility before buying. If you can't find reports from existing Linux owners of a given model, learn what chipsets the notebook uses, particularly for video and sound, and thoroughly investigate those chipsets with respect to Linux support. These steps can save you hours of grief or the need to return the computer.
IN THIS PART
A Linux Device Drivers 607
B Hardware Manufacturers (List of Hardware Manufacturers) 625
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