en/boot-installer/parameters.xml

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 <sect1 id="boot-parms"><title>Boot Parameters</title>
<para>

Boot parameters are Linux kernel parameters which are generally used
to make sure that peripherals are dealt with properly.  For the most
part, the kernel can auto-detect information about your peripherals.
However, in some cases you'll have to help the kernel a bit.

</para><para>

If this is the first time you're booting the system, try the default
boot parameters (i.e., don't try setting parameters) and see if it works
correctly. It probably will.  If not, you can reboot later and look for
any special parameters that inform the system about your hardware.

</para><para>

Information on many boot parameters can be found in the
<ulink url="http://www.tldp.org/HOWTO/BootPrompt-HOWTO.html"> Linux
BootPrompt HOWTO</ulink>, including tips for obscure hardware.  This
section contains only a sketch of the most salient parameters.  Some
common gotchas are included below in
<xref linkend="boot-troubleshooting"/>.

</para><para>

When the kernel boots, a message

<informalexample><screen>
Memory:<replaceable>avail</replaceable>k/<replaceable>total</replaceable>k available
</screen></informalexample>

should be emitted early in the process.
<replaceable>total</replaceable> should match the total amount of RAM,
in kilobytes.  If this doesn't match the actual amount of RAM you have
installed, you need to use the
<userinput>mem=<replaceable>ram</replaceable></userinput> parameter,
where <replaceable>ram</replaceable> is set to the amount of memory,
suffixed with <quote>k</quote> for kilobytes, or <quote>m</quote> for
megabytes.  For example, both <userinput>mem=65536k</userinput> and
<userinput>mem=64m</userinput> mean 64MB of RAM.

</para><para condition="supports-serial-console">

If you are booting with a serial console, generally the kernel will
autodetect
this<phrase arch="mipsel"> (although not on DECstations)</phrase>.
If you have a videocard (framebuffer) and a keyboard also attached to
the computer which you wish to boot via serial console, you may have
to pass the
<userinput>console=<replaceable>device</replaceable></userinput>
argument to the kernel, where <replaceable>device</replaceable> is
your serial device, which is usually something like
<filename>ttyS0</filename>.

</para><para arch="sparc">

For &arch-title; the serial devices are <filename>ttya</filename> or
<filename>ttyb</filename>.
Alternatively, set the <envar>input-device</envar> and
<envar>output-device</envar> OpenPROM variables to
<filename>ttya</filename>.

</para>


  <sect2 id="installer-args"><title>Debian Installer Parameters</title>
<para>

The installation system recognizes a few additional boot parameters<footnote>

<para>

With current kernels (2.6.9 or newer) you can use 32 command line options and
32 environment options. If these numbers are exceeded, the kernel will panic.

</para>

</footnote> which may be useful.

</para>

<variablelist>
<varlistentry>
<term>debconf/priority</term>
<listitem><para>

This parameter sets the lowest priority of messages to be displayed.
Short form: <userinput>priority</userinput>

</para><para>

The default installation uses <userinput>priority=high</userinput>.
This means that both high and critical priority messages are shown, but medium
and low priority messages are skipped.
If problems are encountered, the installer adjusts the priority as needed.

</para><para>

If you add <userinput>priority=medium</userinput> as boot parameter, you
will be shown the installation menu and gain more control over the installation.
When <userinput>priority=low</userinput> is used, all messages are shown
(this is equivalent to the <emphasis>expert</emphasis> boot method).
With <userinput>priority=critical</userinput>, the installation system
will display only critical messages and try to do the right thing without fuss.

</para></listitem>
</varlistentry>


<varlistentry>
<term>DEBIAN_FRONTEND</term>
<listitem><para>

This boot parameter controls the type of user interface used for the
installer. The current possible parameter settings are:

<itemizedlist>
<listitem>
<para><userinput>DEBIAN_FRONTEND=noninteractive</userinput></para>
</listitem><listitem>
<para><userinput>DEBIAN_FRONTEND=text</userinput></para>
</listitem><listitem>
<para><userinput>DEBIAN_FRONTEND=newt</userinput></para>
</listitem><listitem>
<para><userinput>DEBIAN_FRONTEND=slang</userinput></para>
</listitem><listitem>
<para><userinput>DEBIAN_FRONTEND=ncurses</userinput></para>
</listitem><listitem>
<para><userinput>DEBIAN_FRONTEND=bogl</userinput></para>
</listitem><listitem>
<para><userinput>DEBIAN_FRONTEND=gtk</userinput></para>
</listitem><listitem>
<para><userinput>DEBIAN_FRONTEND=corba</userinput></para>
</listitem>
</itemizedlist>

The default front end is <userinput>DEBIAN_FRONTEND=newt</userinput>.
<userinput>DEBIAN_FRONTEND=text</userinput> may be preferable for
serial console installs. Generally only the
<userinput>newt</userinput> frontend is available on default install
media, so this is not very useful right now.

</para></listitem>
</varlistentry>


<varlistentry>
<term>BOOT_DEBUG</term>
<listitem><para>

Setting this boot parameter to 2 will cause the installer's boot process
to be verbosely logged. Setting it to 3 makes debug shells
available at strategic points in the boot process. (Exit the shells to
continue the boot process.)

<variablelist>
<varlistentry>
<term><userinput>BOOT_DEBUG=0</userinput></term>
<listitem><para>This is the default.</para></listitem>
</varlistentry>

<varlistentry>
<term><userinput>BOOT_DEBUG=1</userinput></term>
<listitem><para>More verbose than usual.</para></listitem>
</varlistentry>

<varlistentry>
<term><userinput>BOOT_DEBUG=2</userinput></term>
<listitem><para>Lots of debugging information.</para></listitem>
</varlistentry>

<varlistentry>
<term><userinput>BOOT_DEBUG=3</userinput></term>
<listitem><para>

Shells are run at various points in the boot process to allow detailed
debugging. Exit the shell to continue the boot.

</para></listitem>
</varlistentry>
</variablelist>

</para></listitem>
</varlistentry>


<varlistentry>
<term>INSTALL_MEDIA_DEV</term>
<listitem><para>

The value of the parameter is the path to the device to load the
Debian installer from. For example,
<userinput>INSTALL_MEDIA_DEV=/dev/floppy/0</userinput>

</para><para>

The boot floppy, which normally scans all floppies it can to find the
root floppy, can be overridden by this parameter to only look at the
one device.

</para></listitem>
</varlistentry>

<varlistentry>
<term>debian-installer/framebuffer</term>
<listitem><para>

Some architectures use the kernel framebuffer to offer installation in
a number of languages. If framebuffer causes a problem on your system
you can disable the feature by the parameter
<userinput>debian-installer/framebuffer=false</userinput>, or
<userinput>fb=false</userinput> for short. Problem symptoms are error messages
about bterm or bogl, a blank screen, or a freeze within a few minutes after
starting the install.

</para><para arch="x86">

The <userinput>video=vga16:off</userinput> argument may also be used
to disable the kernel's use of the framebuffer. Such problems have been
reported on a Dell Inspiron with Mobile Radeon card.

</para><para arch="m68k">

Such problems have been reported on the Amiga 1200 and SE/30.

</para><para arch="hppa">

Such problems have been reported on hppa.

</para><note arch="sparc"><para>

Because of display problems on some systems, framebuffer support is
<emphasis>disabled by default</emphasis> for &arch-title;. This can result
in ugly display on systems that do properly support the framebuffer, like
those with ATI graphical cards.
If you see display problems in the installer, you can try booting with
parameter <userinput>debian-installer/framebuffer=true</userinput> or
<userinput>fb=true</userinput> for short.

</para></note></listitem>
</varlistentry>

<varlistentry>
<term>debian-installer/theme</term>
<listitem><para>

A theme determines how the user interface of the installer looks (colors,
icons, etc.). What themes are available differs per frontend.  Currently
both the newt and gtk frontends only have a <quote>dark</quote> theme that was
designed for visually impaired users. Set the theme by booting with parameter
<userinput>debian-installer/theme=<replaceable>dark</replaceable></userinput>
or <userinput>theme=<replaceable>dark</replaceable></userinput>.

</para></listitem>
</varlistentry>

<varlistentry>
<term>debian-installer/probe/usb</term>
<listitem><para>

Set to <userinput>false</userinput> to prevent probing for USB on
boot, if that causes problems.

</para></listitem>
</varlistentry>

<varlistentry>
<term>netcfg/disable_dhcp</term>
<listitem><para>

By default, the &d-i; automatically probes for network configuration
via DHCP. If the probe succeeds, you won't have a chance to review and
change the obtained settings. You can get to the manual network setup
only in case the DHCP probe fails.

</para><para>

If you have a DHCP server on your local network, but want to avoid it
because e.g. it gives wrong answers, you can use the parameter
<userinput>netcfg/disable_dhcp=true</userinput> to prevent configuring
the network with DHCP and to enter the information manually.

</para></listitem>
</varlistentry>

<varlistentry>
<term>hw-detect/start_pcmcia</term>
<listitem><para>

Set to <userinput>false</userinput> to prevent starting PCMCIA
services, if that causes problems. Some laptops are well known for
this misbehavior.

</para></listitem>
</varlistentry>

<varlistentry>
<term>preseed/url</term>
<listitem><para>

Specify the url to a preconfiguration file to download and use in
automating the install. See <xref linkend="automatic-install"/>.
Short form: <userinput>url</userinput>

</para></listitem>
</varlistentry>

<varlistentry>
<term>preseed/file</term>
<listitem><para>

Specify the path to a preconfiguration file to load to
automating the install. See <xref linkend="automatic-install"/>.
Short form: <userinput>file</userinput>

</para></listitem>
</varlistentry>

<varlistentry>
<term>auto-install/enabled</term>
<listitem><para>

Delay questions that are normally asked before preseeding is possible until
after the network is configured. Short form: <userinput>auto=true</userinput>
See <xref linkend="preseed-auto"/> for details about using this to
automate installs.

</para></listitem>
</varlistentry>

<varlistentry>
<term>cdrom-detect/eject</term>
<listitem><para>

By default, before rebooting, &d-i; automatically ejects the optical
media used during the installation. This can be unnecessary if the system
does not automatically boot off the CD. In some cases it may even be
undesirable, for example if the optical drive cannot reinsert the media
itself and the user is not there to do it manually. Many slot loading,
slim-line, and caddy style drives cannot reload media automatically.

</para><para>

Set to <userinput>false</userinput> to disable automatic ejection, and
be aware that you may need to ensure that the system does not
automatically boot from the optical drive after the initial
installation.

</para></listitem>
</varlistentry>

<varlistentry>
<term>ramdisk_size</term>
<listitem><para>

If you are using a 2.2.x kernel, you may need to set &ramdisksize;.

</para></listitem>
</varlistentry>

<varlistentry condition="g-i">
<term>mouse/left</term>
<listitem><para>

For the gtk frontend (graphical installer), users can switch the mouse to
left-handed operation by setting this parameter to <userinput>true</userinput>.

</para></listitem>
</varlistentry>

<varlistentry condition="g-i">
<term>directfb/hw-accel</term>
<listitem><para>

For the gtk frontend (graphical installer), hardware acceleration in directfb
is disabled by default. To enable it, set this parameter to
<userinput>true</userinput> when booting the installer.

</para></listitem>
</varlistentry>

<varlistentry>
<term>rescue/enable</term>
<listitem><para>

Set to <userinput>true</userinput> to enter rescue mode rather than
performing a normal installation. See <xref linkend="rescue"/>.

</para></listitem>
</varlistentry>

</variablelist>
  </sect2>

  <sect2 id="module-parms"><title>Passing parameters to kernel modules</title>
<para>

If drivers are compiled into the kernel, you can pass parameters to them
as described in the kernel documentation. However, if drivers are compiled
as modules and because kernel modules are loaded a bit differently during
an installation than when booting an installed system, it is not possible
to pass parameters to modules as you would normally do. Instead, you need
to use a special syntax recognized by the installer which will then make
sure that the parameters are saved in the proper configuration files and
will thus be used when the modules are actually loaded. The parameters
will also be propagated automatically to the configuration for the installed
system.

</para><para>

Note that it is now quite rare that parameters need to be passed to modules.
In most cases the kernel will be able to probe the hardware present in a
system and set good defaults that way. However, in some situations it may
still be needed to set parameters manually.

</para><para>

The syntax to use to set parameters for modules is:

<informalexample><screen>
<replaceable>module_name</replaceable>.<replaceable>parameter_name</replaceable>=<replaceable>value</replaceable>
</screen></informalexample>

If you need to pass multiple parameters to the same or different modules,
just repeat this. For example, to set an old 3Com network interface card
to use the BNC (coax) connector and IRQ 10, you would pass:

<informalexample><screen>
3c509.xcvr=3 3c509.irq=10
</screen></informalexample>

</para>
  </sect2>
 </sect1>

1	toff	5236	<!-- retain these comments for translator revision tracking -->
2	joeyh	11648	<!-- $Id$ -->
3	toff	5236
4			<sect1 id="boot-parms"><title>Boot Parameters</title>
5			<para>
6
7			Boot parameters are Linux kernel parameters which are generally used
8			to make sure that peripherals are dealt with properly. For the most
9			part, the kernel can auto-detect information about your peripherals.
10			However, in some cases you'll have to help the kernel a bit.
11
12			</para><para>
13
14			If this is the first time you're booting the system, try the default
15	joeyh	18638	boot parameters (i.e., don't try setting parameters) and see if it works
16	toff	5236	correctly. It probably will. If not, you can reboot later and look for
17			any special parameters that inform the system about your hardware.
18
19			</para><para>
20
21	fjp	28672	Information on many boot parameters can be found in the
22	toff	5907	<ulink url="http://www.tldp.org/HOWTO/BootPrompt-HOWTO.html"> Linux
23	toff	5236	BootPrompt HOWTO</ulink>, including tips for obscure hardware. This
24			section contains only a sketch of the most salient parameters. Some
25	fjp	28672	common gotchas are included below in
26	toff	5338	<xref linkend="boot-troubleshooting"/>.
27	toff	5236
28			</para><para>
29
30	fjp	28672	When the kernel boots, a message
31	toff	5236
32			<informalexample><screen>
33	fjp	28672	Memory:<replaceable>avail</replaceable>k/<replaceable>total</replaceable>k available
34	toff	5236	</screen></informalexample>
35
36			should be emitted early in the process.
37			<replaceable>total</replaceable> should match the total amount of RAM,
38			in kilobytes. If this doesn't match the actual amount of RAM you have
39			installed, you need to use the
40			<userinput>mem=<replaceable>ram</replaceable></userinput> parameter,
41			where <replaceable>ram</replaceable> is set to the amount of memory,
42	fjp	28997	suffixed with <quote>k</quote> for kilobytes, or <quote>m</quote> for
43			megabytes. For example, both <userinput>mem=65536k</userinput> and
44	toff	5236	<userinput>mem=64m</userinput> mean 64MB of RAM.
45
46			</para><para condition="supports-serial-console">
47
48			If you are booting with a serial console, generally the kernel will
49	holger-guest	25171	autodetect
50			this<phrase arch="mipsel"> (although not on DECstations)</phrase>.
51	toff	5236	If you have a videocard (framebuffer) and a keyboard also attached to
52			the computer which you wish to boot via serial console, you may have
53			to pass the
54			<userinput>console=<replaceable>device</replaceable></userinput>
55			argument to the kernel, where <replaceable>device</replaceable> is
56	mck	5692	your serial device, which is usually something like
57			<filename>ttyS0</filename>.
58	toff	5236
59	toff	5338	</para><para arch="sparc">
60	toff	5236
61	mck-guest	7337	For &arch-title; the serial devices are <filename>ttya</filename> or
62	mck	5692	<filename>ttyb</filename>.
63			Alternatively, set the <envar>input-device</envar> and
64			<envar>output-device</envar> OpenPROM variables to
65			<filename>ttya</filename>.
66	toff	5236
67			</para>
68
69
70	joeyh	18638	<sect2 id="installer-args"><title>Debian Installer Parameters</title>
71	toff	5236	<para>
72
73	fjpop-guest	23207	The installation system recognizes a few additional boot parameters<footnote>
74	toff	5236
75	fjpop-guest	23207	<para>
76
77	fjp	42302	With current kernels (2.6.9 or newer) you can use 32 command line options and
78			32 environment options. If these numbers are exceeded, the kernel will panic.
79	fjpop-guest	23207
80	toff	5236	</para>
81
82	fjp	28672	</footnote> which may be useful.
83	fjpop-guest	23207
84			</para>
85
86	toff	5236	<variablelist>
87			<varlistentry>
88	joeyh	18636	<term>debconf/priority</term>
89	toff	5236	<listitem><para>
90
91	fjp	28672	This parameter sets the lowest priority of messages to be displayed.
92	joeyh	38231	Short form: <userinput>priority</userinput>
93	toff	5236
94	toff	5907	</para><para>
95
96	joeyh	38231	The default installation uses <userinput>priority=high</userinput>.
97	fjpop-guest	14359	This means that both high and critical priority messages are shown, but medium
98	fjp	28672	and low priority messages are skipped.
99	fjpop-guest	14359	If problems are encountered, the installer adjusts the priority as needed.
100	toff	5907
101			</para><para>
102
103	joeyh	38231	If you add <userinput>priority=medium</userinput> as boot parameter, you
104	fjpop-guest	14359	will be shown the installation menu and gain more control over the installation.
105	joeyh	38231	When <userinput>priority=low</userinput> is used, all messages are shown
106	fjpop-guest	14359	(this is equivalent to the <emphasis>expert</emphasis> boot method).
107	joeyh	38231	With <userinput>priority=critical</userinput>, the installation system
108	fjpop-guest	14359	will display only critical messages and try to do the right thing without fuss.
109	toff	5907
110	toff	5236	</para></listitem>
111			</varlistentry>
112
113	toff	5907
114	toff	5236	<varlistentry>
115	joeyh	22236	<term>DEBIAN_FRONTEND</term>
116	toff	5907	<listitem><para>
117	toff	5236
118	toff	5907	This boot parameter controls the type of user interface used for the
119			installer. The current possible parameter settings are:
120
121			<itemizedlist>
122	mck-guest	7337	<listitem>
123	joeyh	22236	<para><userinput>DEBIAN_FRONTEND=noninteractive</userinput></para>
124	mck-guest	7337	</listitem><listitem>
125	joeyh	22236	<para><userinput>DEBIAN_FRONTEND=text</userinput></para>
126	mck-guest	7337	</listitem><listitem>
127	joeyh	22236	<para><userinput>DEBIAN_FRONTEND=newt</userinput></para>
128	mck-guest	7337	</listitem><listitem>
129	joeyh	22236	<para><userinput>DEBIAN_FRONTEND=slang</userinput></para>
130	mck-guest	7337	</listitem><listitem>
131	joeyh	22236	<para><userinput>DEBIAN_FRONTEND=ncurses</userinput></para>
132	mck-guest	7337	</listitem><listitem>
133	joeyh	22236	<para><userinput>DEBIAN_FRONTEND=bogl</userinput></para>
134	mck-guest	7337	</listitem><listitem>
135	joeyh	22236	<para><userinput>DEBIAN_FRONTEND=gtk</userinput></para>
136	mck-guest	7337	</listitem><listitem>
137	joeyh	22236	<para><userinput>DEBIAN_FRONTEND=corba</userinput></para>
138	mck-guest	7337	</listitem>
139	toff	5907	</itemizedlist>
140
141	joeyh	22236	The default front end is <userinput>DEBIAN_FRONTEND=newt</userinput>.
142			<userinput>DEBIAN_FRONTEND=text</userinput> may be preferable for
143	joeyh	18636	serial console installs. Generally only the
144			<userinput>newt</userinput> frontend is available on default install
145	mck-guest	14350	media, so this is not very useful right now.
146	toff	5907
147			</para></listitem>
148			</varlistentry>
149
150
151			<varlistentry>
152			<term>BOOT_DEBUG</term>
153	toff	5236	<listitem><para>
154
155	joeyh	29270	Setting this boot parameter to 2 will cause the installer's boot process
156			to be verbosely logged. Setting it to 3 makes debug shells
157	joeyh	29269	available at strategic points in the boot process. (Exit the shells to
158			continue the boot process.)
159	toff	5236
160	toff	5907	<variablelist>
161			<varlistentry>
162	mck-guest	9780	<term><userinput>BOOT_DEBUG=0</userinput></term>
163	toff	5907	<listitem><para>This is the default.</para></listitem>
164			</varlistentry>
165
166			<varlistentry>
167	mck-guest	9780	<term><userinput>BOOT_DEBUG=1</userinput></term>
168	toff	5907	<listitem><para>More verbose than usual.</para></listitem>
169			</varlistentry>
170
171			<varlistentry>
172	mck-guest	9780	<term><userinput>BOOT_DEBUG=2</userinput></term>
173	toff	5907	<listitem><para>Lots of debugging information.</para></listitem>
174			</varlistentry>
175
176			<varlistentry>
177	mck-guest	9780	<term><userinput>BOOT_DEBUG=3</userinput></term>
178	toff	5907	<listitem><para>
179
180			Shells are run at various points in the boot process to allow detailed
181			debugging. Exit the shell to continue the boot.
182
183	toff	5236	</para></listitem>
184			</varlistentry>
185	toff	5907	</variablelist>
186	toff	5236
187	toff	5907	</para></listitem>
188			</varlistentry>
189
190
191	toff	5236	<varlistentry>
192	toff	5907	<term>INSTALL_MEDIA_DEV</term>
193	toff	5236	<listitem><para>
194
195	toff	5907	The value of the parameter is the path to the device to load the
196			Debian installer from. For example,
197			<userinput>INSTALL_MEDIA_DEV=/dev/floppy/0</userinput>
198	toff	5236
199	toff	5907	</para><para>
200
201	joeyh	36744	The boot floppy, which normally scans all floppies it can to find the
202			root floppy, can be overridden by this parameter to only look at the
203			one device.
204	toff	5907
205	toff	5236	</para></listitem>
206			</varlistentry>
207
208			<varlistentry>
209	mck-guest	9780	<term>debian-installer/framebuffer</term>
210	toff	5236	<listitem><para>
211
212			Some architectures use the kernel framebuffer to offer installation in
213			a number of languages. If framebuffer causes a problem on your system
214	mck-guest	9780	you can disable the feature by the parameter
215	joeyh	38231	<userinput>debian-installer/framebuffer=false</userinput>, or
216			<userinput>fb=false</userinput> for short. Problem symptoms are error messages
217			about bterm or bogl, a blank screen, or a freeze within a few minutes after
218			starting the install.
219	toff	5236
220	fjp	39614	</para><para arch="x86">
221	toff	5236
222	toff	5338	The <userinput>video=vga16:off</userinput> argument may also be used
223	fjp	38289	to disable the kernel's use of the framebuffer. Such problems have been
224	joeyh	38231	reported on a Dell Inspiron with Mobile Radeon card.
225	toff	5236
226			</para><para arch="m68k">
227
228			Such problems have been reported on the Amiga 1200 and SE/30.
229
230			</para><para arch="hppa">
231
232			Such problems have been reported on hppa.
233
234	fjpop-guest	26488	</para><note arch="sparc"><para>
235
236			Because of display problems on some systems, framebuffer support is
237			<emphasis>disabled by default</emphasis> for &arch-title;. This can result
238			in ugly display on systems that do properly support the framebuffer, like
239			those with ATI graphical cards.
240			If you see display problems in the installer, you can try booting with
241	fjp	39461	parameter <userinput>debian-installer/framebuffer=true</userinput> or
242			<userinput>fb=true</userinput> for short.
243	fjpop-guest	26488
244			</para></note></listitem>
245	toff	5236	</varlistentry>
246
247	mck-guest	14350	<varlistentry>
248	fjp	40875	<term>debian-installer/theme</term>
249			<listitem><para>
250
251			A theme determines how the user interface of the installer looks (colors,
252			icons, etc.). What themes are available differs per frontend. Currently
253			both the newt and gtk frontends only have a <quote>dark</quote> theme that was
254			designed for visually impaired users. Set the theme by booting with parameter
255			<userinput>debian-installer/theme=<replaceable>dark</replaceable></userinput>
256			or <userinput>theme=<replaceable>dark</replaceable></userinput>.
257
258			</para></listitem>
259			</varlistentry>
260
261			<varlistentry>
262	mck-guest	14350	<term>debian-installer/probe/usb</term>
263			<listitem><para>
264
265			Set to <userinput>false</userinput> to prevent probing for USB on
266			boot, if that causes problems.
267
268			</para></listitem>
269			</varlistentry>
270
271			<varlistentry>
272	joshk	17333	<term>netcfg/disable_dhcp</term>
273	mck-guest	14350	<listitem><para>
274
275			By default, the &d-i; automatically probes for network configuration
276			via DHCP. If the probe succeeds, you won't have a chance to review and
277	fjpop-guest	22935	change the obtained settings. You can get to the manual network setup
278	mck-guest	14350	only in case the DHCP probe fails.
279
280			</para><para>
281
282			If you have a DHCP server on your local network, but want to avoid it
283			because e.g. it gives wrong answers, you can use the parameter
284	joshk	17333	<userinput>netcfg/disable_dhcp=true</userinput> to prevent configuring
285	mck-guest	14350	the network with DHCP and to enter the information manually.
286
287			</para></listitem>
288			</varlistentry>
289
290			<varlistentry>
291			<term>hw-detect/start_pcmcia</term>
292			<listitem><para>
293
294			Set to <userinput>false</userinput> to prevent starting PCMCIA
295			services, if that causes problems. Some laptops are well known for
296	fjpop-guest	22935	this misbehavior.
297	mck-guest	14350
298			</para></listitem>
299			</varlistentry>
300
301	smarenka	18672	<varlistentry>
302	joeyh	20054	<term>preseed/url</term>
303			<listitem><para>
304
305			Specify the url to a preconfiguration file to download and use in
306			automating the install. See <xref linkend="automatic-install"/>.
307	joeyh	38231	Short form: <userinput>url</userinput>
308	joeyh	20054
309			</para></listitem>
310			</varlistentry>
311
312			<varlistentry>
313	fjp	42367	<term>preseed/file</term>
314	joeyh	20054	<listitem><para>
315
316	fjp	42367	Specify the path to a preconfiguration file to load to
317			automating the install. See <xref linkend="automatic-install"/>.
318			Short form: <userinput>file</userinput>
319	joeyh	20054
320			</para></listitem>
321			</varlistentry>
322
323	fjp	33725	<varlistentry>
324	fjp	42367	<term>auto-install/enabled</term>
325	joeyh	42365	<listitem><para>
326
327	fjp	42367	Delay questions that are normally asked before preseeding is possible until
328			after the network is configured. Short form: <userinput>auto=true</userinput>
329			See <xref linkend="preseed-auto"/> for details about using this to
330			automate installs.
331	joeyh	42365
332			</para></listitem>
333			</varlistentry>
334
335			<varlistentry>
336	fjpop-guest	27076	<term>cdrom-detect/eject</term>
337			<listitem><para>
338
339			By default, before rebooting, &d-i; automatically ejects the optical
340			media used during the installation. This can be unnecessary if the system
341			does not automatically boot off the CD. In some cases it may even be
342			undesirable, for example if the optical drive cannot reinsert the media
343			itself and the user is not there to do it manually. Many slot loading,
344	fjp	28672	slim-line, and caddy style drives cannot reload media automatically.
345	fjpop-guest	27076
346			</para><para>
347
348			Set to <userinput>false</userinput> to disable automatic ejection, and
349			be aware that you may need to ensure that the system does not
350			automatically boot from the optical drive after the initial
351			installation.
352
353			</para></listitem>
354			</varlistentry>
355
356	joeyh	20054	<varlistentry>
357	smarenka	18672	<term>ramdisk_size</term>
358			<listitem><para>
359
360			If you are using a 2.2.x kernel, you may need to set &ramdisksize;.
361
362			</para></listitem>
363			</varlistentry>
364
365	fjp	42824	<varlistentry condition="g-i">
366			<term>mouse/left</term>
367			<listitem><para>
368
369			For the gtk frontend (graphical installer), users can switch the mouse to
370			left-handed operation by setting this parameter to <userinput>true</userinput>.
371
372			</para></listitem>
373			</varlistentry>
374
375			<varlistentry condition="g-i">
376	fjp	40875	<term>directfb/hw-accel</term>
377			<listitem><para>
378
379			For the gtk frontend (graphical installer), hardware acceleration in directfb
380			is disabled by default. To enable it, set this parameter to
381			<userinput>true</userinput> when booting the installer.
382
383			</para></listitem>
384			</varlistentry>
385
386			<varlistentry>
387	cjwatson	28715	<term>rescue/enable</term>
388			<listitem><para>
389
390			Set to <userinput>true</userinput> to enter rescue mode rather than
391			performing a normal installation. See <xref linkend="rescue"/>.
392
393			</para></listitem>
394			</varlistentry>
395
396	toff	5236	</variablelist>
397			</sect2>
398	fjp	42485
399			<sect2 id="module-parms"><title>Passing parameters to kernel modules</title>
400			<para>
401
402			If drivers are compiled into the kernel, you can pass parameters to them
403			as described in the kernel documentation. However, if drivers are compiled
404			as modules and because kernel modules are loaded a bit differently during
405			an installation than when booting an installed system, it is not possible
406			to pass parameters to modules as you would normally do. Instead, you need
407			to use a special syntax recognized by the installer which will then make
408			sure that the parameters are saved in the proper configuration files and
409			will thus be used when the modules are actually loaded. The parameters
410			will also be propagated automatically to the configuration for the installed
411			system.
412
413			</para><para>
414
415			Note that it is now quite rare that parameters need to be passed to modules.
416			In most cases the kernel will be able to probe the hardware present in a
417			system and set good defaults that way. However, in some situations it may
418			still be needed to set parameters manually.
419
420			</para><para>
421
422			The syntax to use to set parameters for modules is:
423
424			<informalexample><screen>
425			<replaceable>module_name</replaceable>.<replaceable>parameter_name</replaceable>=<replaceable>value</replaceable>
426			</screen></informalexample>
427
428			If you need to pass multiple parameters to the same or different modules,
429			just repeat this. For example, to set an old 3Com network interface card
430			to use the BNC (coax) connector and IRQ 10, you would pass:
431
432			<informalexample><screen>
433			3c509.xcvr=3 3c509.irq=10
434			</screen></informalexample>
435
436			</para>
437			</sect2>
438	toff	5236	</sect1>
439