advanced configuration options in redhar-config-xfree86

[Mike A. Harris]

On Wed, 8 Oct 2003, Alan Cox wrote:

>> redhat-config-xfree86 in RH9 has many advanced configurtion options - 
>> ability to specify monitor refresh rates, DPI, video memory size, etc.
>> 
>> Why all these options were removed in Fedora?
>
>videoram is still settable using the command line option only. That or
>someone forgot to update the texts. The DPI are still present in the 
>program too (including the measure your monitor dialog).

Not for long...  ;o)

The Radeon driver will ignore any user specified VideoRAM setting 
provided in the config file.  The "radeon" driver properly 
autodetects video memory amount on all known and supported Radeon 
video hardware, and the only usage of the VideoRAM option by 
users has resulted in bogus bug reports for me and/or John to 
troubleshoot, so the option is now killed for this driver.  The 
option will be killed for other drivers in the future also.

My plan is to only allow the VideoRAM option to be used for 
drivers to which there are known problems with detecting video 
memory, and to restrict its usage to the specific problematic 
hardware, and also to restrict the range of values to sensible 
values that real hardware was released for.

There are only 3 valid uses of the VideoRAM setting aside from 
that which I can think of:

1) The i8xx driver allows this option to specify how much system 
memory is assigned for video memory on UMA systems.  That is 
fine, and aparently works ok, and has proper limit checking to 
ensure users can't say they have 128Mb of memory if the system 
only permits say 64Mb.

2) User has bad video memory of which the bad memory is in the 
upper 32Mb of a 64Mb card for example, and wants to limit video 
memory to 32Mb in order to use the card safely.  This is a very 
rare occurance, and few people are likely to realize they can 
even do this.  In these cases they can recompile the driver, or 
politely ask me to build them a custom driver if they like, and 
I'd be more than glad to do so.  In the future, I'll probably 
enhance the option to allow users to choose power-of-2 multiples 
of memory less than the hardware's true amount within some 
boundary for this.

3) Developers working on video drivers sometimes use this option 
to limit video memory for various reasons such as testing 
performance of thigns in less memory, etc.  - in this case, 
they're a developer and can are compiling their own driver 
anyway.


>Refresh rate is lacking - which is a problem because many
>countries have 72Hz health and safety minimums for workers using
>crt monitors and the tools dont seem to generate 72Hz or better
>in all cases they can automatically.

The refresh rate can be controlled via the xrandr commandline 
tool, and the panel applet tool.  The refresh rate can be 
restricted to 72Hz or higher, by making 72Hz the lower limit of 
the vertical refresh in the config file (VertRefresh).

I definitely agree users should be able to choose their refresh 
rate easily somehow, and that the default should be as high as 
possible that the given hardware combination they're using.  The 
X server automatically does that if the config file ranges are 
specified correctly, but the user may want to limit the lower 
limit to keep it within EU safety range.


-- 
Mike A. Harris     ftp://people.redhat.com/mharris
OS Systems Engineer - XFree86 maintainer - Red Hat