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Home > Archive > Cheap Linux Hardware > July 2007 > Problem with monitor resolution.
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Problem with monitor resolution.
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| Martin Sondergaard 2007-07-02, 1:16 am |
| I've got a nice big CRT monitor, which I normally use
at a resolution of 1600 * 1200 at 75Hz.
Linux fails to take advantage of this monitor.
The highest resolution that it offers me is 1280 * 1024 at 60Hz.
This is bad because at 60 Hz the screen is unsteady, its flickering.
So the monitor looks much better in Windows.
When I installed Ubuntu Linux, the installation program asked me
to specify a "maximum" resolution for my monitor.
I accidentally set it too low. I don't remember what I set it to,
but I wonder if I am now stuck with that resolution.
Do you think it would help if I reinstall Ubuntu?
Or maybe thats not the problem. Maybe Ubuntu Linux
just doesn't have a good driver for the graphics card.
If thats the problem, then I will probably need to buy
a new graphics card, if I want to use Linux.
Is there a better solution?
I looked at Device Manager, and I think that Ubuntu is unable
to identify the motherboard. I'm not sure if this computer
has a separate graphics card, or if its using on-board graphics.
--
Martin Sondergaard,
London.
| |
| Henrik Carlqvist 2007-07-02, 1:16 am |
| Martin Sondergaard <donotemailme@nowhere.com> wrote:
> I've got a nice big CRT monitor, which I normally use at a resolution of
> 1600 * 1200 at 75Hz.
Would it be possible to run the monitor at a higher refresh rate? Most
people find 75 Hz on a CRT monitor to be flickering. Usually a refresh
rate between 85 Hz and 100 Hz is to prefer on CRT monitors.
> Linux fails to take advantage of this monitor. The highest resolution
> that it offers me is 1280 * 1024 at 60Hz. This is bad because at 60 Hz
> the screen is unsteady, its flickering.
This could be a settings problem or a driver problem with the driver for
your graphics card. Maybe you are not using the right driver?
> So the monitor looks much better in Windows.
Yes, 60 Hz is really awful on CRT. The low resolution doesn't make things
better.
> When I installed Ubuntu Linux, the installation program asked me to
> specify a "maximum" resolution for my monitor. I accidentally set it too
> low. I don't remember what I set it to, but I wonder if I am now stuck
> with that resolution.
No, you should be able to change those settings.
> Do you think it would help if I reinstall Ubuntu?
That would be one way to change the settings, but it is most likely
overkill. I'm not familiar with ubuntu, maybe it has some graphic tool to
change your graphics settings for X. If it doesn't have any such tool, at
least you should be able to use a text editor to edit the file xorg.conf.
Usually the file xorg.conf is in the directory /etc/X11.
There are two parts of xorg.conf that are of interest, the monitor section
and the screen section. They look something like this:
Section "Monitor"
Identifier "Fujitsu"
# HorizSync is in kHz unless units are specified. # HorizSync may be a
comma separated list of discrete values, or a # comma separated list of
ranges of values. # NOTE: THE VALUES HERE ARE EXAMPLES ONLY. REFER TO
YOUR MONITOR'S # USER MANUAL FOR THE CORRECT NUMBERS.
HorizSync 30-95
# HorizSync 30-64 # multisync # HorizSync 31.5, 35.2 #
multiple fixed sync frequencies # HorizSync 15-25, 30-50 # multiple
ranges of sync frequencies
# VertRefresh is in Hz unless units are specified. # VertRefresh may be a
comma separated list of discrete values, or a # comma separated list of
ranges of values. # NOTE: THE VALUES HERE ARE EXAMPLES ONLY. REFER TO
YOUR MONITOR'S # USER MANUAL FOR THE CORRECT NUMBERS.
VertRefresh 50-160
EndSection
In the monitor section you specify what your monitor is capable of. If
your monitor is capable of high values it will be able to handle high
resolutionns at high refresh rates.
Then we have the screen section, it looks something like this:
Section "Screen"
Identifier "Screen 1"
Device "Powercolor Radeon 9200"
Monitor "Fujitsu"
DefaultDepth 16
Subsection "Display"
Depth 8
Modes "1280x1024" "1024x768" "800x600" "640x480" ViewPort 0
0
EndSubsection
Subsection "Display"
Depth 16
Modes "1280x1024" "1024x768" "800x600" "640x480" ViewPort 0
0
EndSubsection
Subsection "Display"
Depth 24
Modes "1280x1024" "1024x768" "800x600" "640x480" ViewPort 0
0
EndSubsection
EndSection
In the screen section you choose which resolutions and which color depth
you want to use.
> Maybe Ubuntu Linux just doesn't have a good driver for the graphics
> card.
That could be the case, but to be able to tell this we need to know which
graphics card you have and what driver you are using. The driver is
specified in the device section:
Section "Device"
Identifier "Powercolor Radeon 9200"
Driver "radeon"
#VideoRam 262144
# Insert Clocks lines here if appropriate Option "AGPMode" "4"
Option "EnablePageFlip" "on"
EndSection
Above you can see that I am using the radeon driver for my ATI based card.
> I'm not sure if this computer has a separate graphics card, or if its
> using on-board graphics.
This is probably your biggest problem. To be able to optimize your
installation for your hardware you must know what hardware you have.
It is rather easy to find out what kind of graphics card you have (cat
/proc/pci), but it might be harder to find out what your monitor is
capable of. If you have a manual for your monitor you can usually find
that in a chapter named something like "technical specifications". If your
monitor, your graphics card and your VGA cable supports EDID (also known
as plug and play) X is able to ask your monitor about its capabilities and
you will find those in the log files that X creates. That log file might
be called something like /var/log/Xorg.0.log. In that log file you might
also find information about your graphics card and which driver you are
using.
regards Henrik
--
The address in the header is only to prevent spam. My real address is:
hc1(at)poolhem.se Examples of addresses which go to spammers:
root@localhost postmaster@localhost
| |
| Anton Ertl 2007-07-02, 7:16 am |
| Martin Sondergaard <donotemailme@nowhere.com> writes:
>I've got a nice big CRT monitor, which I normally use
>at a resolution of 1600 * 1200 at 75Hz.
>
>Linux fails to take advantage of this monitor.
>The highest resolution that it offers me is 1280 * 1024 at 60Hz.
>This is bad because at 60 Hz the screen is unsteady, its flickering.
>
>So the monitor looks much better in Windows.
>
>When I installed Ubuntu Linux, the installation program asked me
>to specify a "maximum" resolution for my monitor.
Yes, that's a problem. Nowadays many monitors and graphics cards can
talk to each other using DDC and transmit EDID information about what
the monitor can and cannot do (I have heard that this is not the case
for 16:10 displays, but for 4:3 like the one you have and for 5:4
displays it is).
So one possible approach to your problem is to edit the xorg.conf file
and comment out all the lines that specify what the monitor can do
(e.g., HorizSync and VertRefresh lines), as well as the lines
specifying which modes you want (i.e., Modes lines). Then you have a
good chance that the graphics driver will create a good mode based on
the EDID information from the display.
The other option is to specify the information specific for your
display explicitly, as Henrik Carlqvist showed.
In any case, you will want to test X with the new xorg.conf file. A
good way to do it is to name the new file differently, say
/etc/xorg.conf-test and then start another X server on another virtual
terminal, e.g.:
X :1 -config /etc/xorg.conf-test
This will only show you the classic X mesh background and a mouse
cursor, and nothing else, but that's enough to see whether the
resolution and refresh rate is ok. You can terminate that X server
with Ctrl-Alt-Backspace, or switch to another virtual terminal with
Ctrl-Alt-F1...F10 (typically the original X session is on vt7,
i.e. Ctrl-Alt-F7).
Some graphics drivers (from what I hear, especially proprietary ones)
cannot properly switch virtual terminals, so you might get an unusable
system while testing. Don't worry too much, just reboot and try
again.
- anton
--
M. Anton Ertl Some things have to be seen to be believed
anton@mips.complang.tuwien.ac.at Most things have to be believed to be seen
http://www.complang.tuwien.ac.at/anton/home.html
| |
| Bill Marcum 2007-07-02, 7:17 pm |
| On Mon, 02 Jul 2007 06:27:08 +0100, Martin Sondergaard
<donotemailme@nowhere.com> wrote:
>
>
> I've got a nice big CRT monitor, which I normally use
> at a resolution of 1600 * 1200 at 75Hz.
>
> Linux fails to take advantage of this monitor.
> The highest resolution that it offers me is 1280 * 1024 at 60Hz.
> This is bad because at 60 Hz the screen is unsteady, its flickering.
>
> So the monitor looks much better in Windows.
>
> When I installed Ubuntu Linux, the installation program asked me
> to specify a "maximum" resolution for my monitor.
> I accidentally set it too low. I don't remember what I set it to,
> but I wonder if I am now stuck with that resolution.
> Do you think it would help if I reinstall Ubuntu?
>
No need to reinstall. Just try this command:
sudo dpkg-reconfigure xserver-xorg
--
BOFH excuse #438:
sticky bit has come loose
| |
| Martin Sondergaard 2007-07-05, 7:15 am |
| I, Martin Sondergaard, wrote that I was unable to make use
of my monitor's highest resolution, in Linux.
Thank you for your help with this, folks.
I was glad to get some replies.
I wrote:
Henrik Carlqvist wrote:[vbcol=seagreen]
>
> Would it be possible to run the monitor at a higher refresh rate? Most
> people find 75 Hz on a CRT monitor to be flickering. Usually a refresh
> rate between 85 Hz and 100 Hz is to prefer on CRT monitors.
>
Yes, when I use the monitor on a different PC,
with a good graphics card, I can set it
to 1600 * 1200 at 100 Hz. Its a good monitor.
I may be able to find out the detailed spec of the monitor.
Its a Sony monitor, so they may have a ".pdf" manual for it
on the Sony website. I will look there soon.
However, I suspect that the problem is not that Linux
can't identify the monitor. I think it is that
the graphics system can't make use of it.
Its not a separate graphics card, its on the motherboard.
Adapter type: SiS 730.
Its only got 16 MB of memory, so that may make it limited
in the resolution it can display on the monitor.
(My PC is dual-boot, Windows XP and Linux. I got this data
by by booting into Windows XP.)
I suspect its a poor graphics system, that cannot manage
high refresh rates.
I have noticed that when I boot into Windows,
I can get 1600 * 1200 at 75 Hz, but only
if I use 16 bit color instead of 32 bit.
When I specify that I want to use 32 bit color
then the resolutions available in Windows
are just as limited as the ones in Linux.
Maybe what I need to do, to get high resolution
in Linux, is to reduce the number of colors.
Ubuntu has a graphical program that lets me change
the display resolution. The highest resolution
that it lists is 1280 * 1024 at 60 Hz. Using 32 bit color.
It could be that this program assumes that I want to
use 32 bit color. It doesn't give me any options
to change the number of bits per pixel.
But I may be able to change this in a config file.
If so, this may set it to use a high resolution,
at 16 bits per pixel.
I've not had time to look at any config files yet.
But I hope to do this soon.
--
Martin Sondergaard.
| |
| Henrik Carlqvist 2007-07-05, 7:16 pm |
| Martin Sondergaard <donotemailme@nowhere.com> wrote:
> It could be that this program assumes that I want to
> use 32 bit color. It doesn't give me any options
> to change the number of bits per pixel.
> But I may be able to change this in a config file.
> If so, this may set it to use a high resolution,
> at 16 bits per pixel.
In xorg.conf you choose the number of bits per pixel in the screen
section. Below I have selected 16 bits color depth:
Section "Screen"
Identifier "Screen 1"
Device "Powercolor Radeon 9200"
Monitor "Fujitsu"
DefaultDepth 16
Subsection "Display"
Depth 8
Modes "1280x1024" "1024x768" "800x600" "640x480" ViewPort 0
0
EndSubsection
Subsection "Display"
Depth 16
Modes "1280x1024" "1024x768" "800x600" "640x480" ViewPort 0
0
EndSubsection
Subsection "Display"
Depth 24
Modes "1280x1024" "1024x768" "800x600" "640x480" ViewPort 0
0
EndSubsection
EndSection
My 19 inch crt is only capable of 1280x1024 resolution, you might want to
add 1600x1200 as your first resolution for 16 bit color depth.
regards Henrik
--
The address in the header is only to prevent spam. My real address is:
hc1(at)poolhem.se Examples of addresses which go to spammers:
root@localhost postmaster@localhost
| |
| joseph2k 2007-07-08, 7:15 pm |
| Henrik Carlqvist wrote:
> Martin Sondergaard <donotemailme@nowhere.com> wrote:
>
> Would it be possible to run the monitor at a higher refresh rate? Most
> people find 75 Hz on a CRT monitor to be flickering. Usually a refresh
> rate between 85 Hz and 100 Hz is to prefer on CRT monitors.
>
<SNIP>
> regards Henrik
I will make you a deal, back the refresh rate thing with proper double blind
comparisons and then i will beleive it. Resolution is a different matter.
--
JosephKK
Gegen dummheit kampfen die Gotter Selbst, vergebens.Â_Â_
--Schiller
| |
| Henrik Carlqvist 2007-07-09, 7:15 am |
| joseph2k <quiettechblue@yahoo.com> wrote:
> Henrik Carlqvist wrote:
[vbcol=seagreen]
> I will make you a deal, back the refresh rate thing with proper double
> blind comparisons and then i will beleive it. Resolution is a different
> matter.
Well, I am able to distinguish 75 Hz or lower from 85 Hz or higher on CRT
monitors. If you place two monitors next to each other and have 75 Hz on
one and 85 Hz on the other one I think that even you will be able to tell
which one looks better. If you still are not able to see the difference,
here is a trick:
Look next to the monitor so that the monitor is in the outer part of your
eyes visible field. The human eye is more sensible to flicker in the outer
part of its visible field.
Even if you are not able to see the flickering at 75 Hz when staring right
at the monitor you might still suffer from headache or bad eyes after
looking at such a monitor an entire working day.
regards Henrik
--
The address in the header is only to prevent spam. My real address is:
hc1(at)poolhem.se Examples of addresses which go to spammers:
root@localhost postmaster@localhost
| |
| Peter D. 2007-07-10, 7:15 am |
| on Monday 09 July 2007 16:35
in the Usenet newsgroup comp.os.linux.hardware
Henrik Carlqvist wrote:
[snip]
> Even if you are not able to see the flickering at 75 Hz when staring right
> at the monitor you might still suffer from headache or bad eyes after
> looking at such a monitor an entire working day.
It is possible that 75Hz on your monitor drives you crazy, but the
previous poster can't see anything wrong with it on his monitor.
Different people have different sensitivities. Some people have
no peripheral vision. Some phosphors have longer persistence then
others. Big screens are generally more troublesome, because you
tend to use more peripheral vision.
--
sig goes here...
Peter D.
| |
|
| Martin Sondergaard schreef:
> I've got a nice big CRT monitor, which I normally use
> at a resolution of 1600 * 1200 at 75Hz.
>
> Linux fails to take advantage of this monitor.
> The highest resolution that it offers me is 1280 * 1024 at 60Hz.
> This is bad because at 60 Hz the screen is unsteady, its flickering.
>
> So the monitor looks much better in Windows.
>
> When I installed Ubuntu Linux, the installation program asked me
> to specify a "maximum" resolution for my monitor.
> I accidentally set it too low. I don't remember what I set it to,
> but I wonder if I am now stuck with that resolution.
> Do you think it would help if I reinstall Ubuntu?
>
> Or maybe thats not the problem. Maybe Ubuntu Linux
> just doesn't have a good driver for the graphics card.
> If thats the problem, then I will probably need to buy
> a new graphics card, if I want to use Linux.
>
> Is there a better solution?
>
> I looked at Device Manager, and I think that Ubuntu is unable
> to identify the motherboard. I'm not sure if this computer
> has a separate graphics card, or if its using on-board graphics.
>
> --
> Martin Sondergaard,
> London.
>
>
Hi,
I am using Ubuntu (7.04) as well. A few days ago I bought a new
flatscreen monitor 19 inch, rersolution 1280x1024.
How I got the thing finally installed I can remember anymore, but I
found all the answers, instructions in the Ubuntu formums and Howto's.
So you better look there fot the answer.
Johan Dulac
Netherlands
| |
| Shadow_7 2007-07-26, 7:16 pm |
| >> Linux fails to take advantage of this monitor. The highest resolution[vbcol=seagreen]
Most times that is in your configuration. And depends on if your driver
for your video card supports that resolution and refresh rate. In
addition to your card supporting it. Look in your /var/log/Xorg.0.log
or /var/log/XFree86.0.log file for what it reports as supported modes.
cat /var/log/Xorg.0.log | grep -i "\*mode"
Sure, I could hook up a monitor like that to a PII, with a 4MB Jaton
card, but I wouldn't expect to get much higher than 1024x768 out of it on
that hardware. Even under windows that would be difficult at best to
achieve. If not impossible.
Also note that different drivers support different resolutions. Vesa may
not support all of your video resolutions, but it might support some your
proprietary driver doesn't and vice versa. I have more resolution
options under the Open Source radeon driver than I do under the ati
radeon driver. But I have better acceleration under the ati driver for
my chipset. Of course there's still a little issue with getting 1280x800
out of the fbcon module.
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