Red Hat Bugzilla – Bug 58900
xgamma does not change the gamma value
Last modified: 2007-04-18 12:39:14 EDT
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User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows 98; DVD Owner)
Description of problem:
I want to change the Gamma value used on my monitor, to get more natural colors.
The xgamma program is supposed to be used for that purpose.
But, when I try this command, I get:
xgamma ------------> Returns the current value (1.0 for RGB),
xgamma -gamma 1.8 -> Returns the current value and try to set 1.0 as the new
I have tried integer values, like 2, tried under root, tried to set R, G & B
separately. Nothing works.
My Monitor is a Gateway Vivitron 1572,
The video card is the Intel i810 Chipset, with the proper driver (not the new
Intel driver provided on support.intel.com),
The setting is 1024 x 768 x 24b.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Start a console terminal from the KDE windows, for instance.
2. Use xgamma to get the current value.
3. Use xgamma -gamma "new_value", where "new_value" is a value which is
different from the current value, but not far to avoid any problem of not valid
Actual Results: The screen remains unchanged.
The value in front of the signs <- and -> are 1.0.
Expected Results: The gamma factor should be adjusted.
If you could give me the way to preset the value at boot time, it would be
Do any errors or warnings appear in your X server log file?
You may want to set the Gamma inyour config file instead.
man XF86Config might help
I have regenerated the XF86Config-4 file, first using xconfigurator, then
modifying it manually.
I have added the gamma correction I want, and it is accepted by the driver.
But the xgamma command still does not change anything.
Note that the xvidtune option is not disallowed.
I do not have any error message for the xgamma command in /var/log/X*.log (the
messages I have are for modes automatically tested by the i810 driver and that
are not supported by the monitor or that are removed because I have truncated
the virtual size to 1024x768).
Which XFree86 release are you using:
rpm -qa | grep XFree86
ALso, please attach your config file, and also your XFree86 server log
using the attachment link below.
Created attachment 44377 [details]
Configuration File for XFree86 (Chipset i810 + Gateway Vivitron)
Created attachment 44378 [details]
XFree86 Start log file
I have added the conf & log files for XFree86, including the XFree86 version
It seems that, even if we find "Using gamma correction 1.9" in the log file, it
is not supported by the driver. It could, so, explain why it is unchanged by
the xgamma program (but an more explicit error/warning message should be
On the XFree86 web site, the new i810 driver does not seem to support this
option even today. I do not know how to make an "Enhancement request".
On the Intel support web site, we can find an agp module and an i810 driver,
but I do not know if it is better or not.
Even if it is not the same problem (not a bug), but since it is close to what
you are working on, any idea about "DRI disabled" at the end of the file would
I think you can close the call, provided to forward a request of either change
the documentation or develop some more lines of code...
THE GAMMA CORRECTION ONLY WORKS WORK A DEPTH OF 8 BITS !
IT DOES NOT WORK WITH 16 BITS OR 24 BITS.
Extra information: The DRI module only seems to work in 16 bits (not in 8 nor
For the Gamma correction, I do not understand why it does not work in 24 bits,
because it is hardware-supported by the chipset.
Thanks + Bye.
These features that are missing are something you should request of
XFree86.org to add support for, or to Intel directly. They are not
really bugs, just missing features.
DRI only works on i810 at 16bit depth because that is all the hardware