Date: Tue, 9 Jan 1996 12:06:18 -0500 From: Brian Clapper <bmc@telebase.com> To: freebsd-questions@FreeBSD.org Subject: Re: 16 million colours ? Message-ID: <199601091706.MAA20764@telebase.com.> In-Reply-To: <7858611@toto.iv>
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>>>>> "Jonathan" == Jonathan M Bresler <jmb@FreeBSD.org> writes:
Jonathan> On Tue, 9 Jan 1996, Tony Harverson wrote:
>> Hiya All,
>>
>> I was just wondering if anyone has got xfree86 operating in more than
>> 256 colours.
>>
>> The Init sequence of Xfree86 correctly identifies the card as a cirrus
>> logic gd5430 with 1mb ram.
Jonathan> you have to start the Xserver with the number of bits per pixel
Jonathan> option. i use xdm and have the following line in
Jonathan> usr/X11R6/lib/X11/xdm/Xservers
Jonathan> :0 local /usr/X11R6/bin/X -bpp 16
Jonathan> that's 16 bits per pixel.
Be careful, though. There are some special restrictions on the use of
`-bpp 16' and Cirrus Logic chips. The following is an excerpt from the
"README.cirrus" file. That file is usually located in
/usr/X11R6/lib/X11/doc, assuming you installed the X11 docs; if you didn't,
and you have a Walnut Creek CD-ROM, they're on the live file system (i.e.,
the second CD).
---------- Begin Excerpt
5. Linear addressing and 16bpp/32bpp modes
Currently the unaccelerated 16-bit and 32-bit pixel support in the
SVGA server requires linear addressing. This restriction will
hopefully be removed in a future version. Option "linear" can be
specified in a depth-specific screen section to enable linear
addressing; a MemBase setting (in the device section) is probably also
required. There are a number of different card configurations.
If you have a 542x/543x on the ISA bus, and you have 16Mb or more of
system memory, linear addressing is impossible. 16bpp is out, sorry.
If you have less than 14Mb of memory, you may be able to map the
framebuffer at 14Mb, using `MemBase 0x00e00000'. That's five zeros
after the `e'. Unfortunately many ISA cards don't support linear
addressing.
If you have a 5424/26/28/29 on VESA local bus, the situation is more
complicated. There are two different types of cards w.r.t. linear
addressing:
o Cards that can only map in the lower 16Mb, like cards on the ISA
bus. This is the case with most cards. The same restrictions
apply (i.e. you must have less than 16Mb of memory).
o Cards that connect address line A26 and always map at 64Mb +
14Mb or 64Mb. In this case specify `MemBase 0x04e00000' or
`MemBase 0x04000000'. This assumes you have a VLB motherboard
implementation that implements A26. Alternatively the card may
map to 0x2000000, and recent cards like the 5429 usually map to
0x03e00000 (62Mb).
You will probably have to rely on trial and error. If you have less
than 16Mb memory, the `wrong' membase setting will result in no graph-
ics being displayed, but you can probably exit with ctrl-alt-
backspace.
If you have >= 16Mb memory, the first type of card (and even the
second type with a stupid VLB motherboard) will result in a crash
(probably a spontaneous hard reboot).
---------- End Excerpt
There's quite a bit more information than that. I'd suggest reading that
document thoroughly before trying anything.
----
Brian Clapper, bmc@telebase.com, http://www.netaxs.com/~bmc/
Subpoena,n .:
From the root "sub", below, and the Latin "poena" for male
organ or penis. Therefore, "below the penis" or "by the balls."
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