NVIDIA driver and DPMS: backlight never switches off

[D. D. Brierton]

On Wed, 2006-01-11 at 18:57 -0500, Kanwar Ranbir Sandhu wrote: 
> On Wed, 2006-11-01 at 22:23 +0000, D. D. Brierton wrote:
> > Well, I just built and installed the 8178 driver and there is still no
> > improvement. The one thing that I didn't mention before is that I have
> > in /etc/modprobe.conf the following:
> > 
> > options nvidia NVreg_SoftEDIDs=0 NVreg_Mobile=0
> > 
> > as that is necessary to prevent a garbled screen.
> 
> That's new to me!
> 
> I took a look at the docs, and based on what it says, the above driver
> options are only necessary if the EDID provided by your monitor can't be
> trusted or doesn't work.  However, I personally haven't experienced any
> problems with the auto detection, so I leave the UseEdidFreqs at default
> (true).

The problem which necessitates the "options nvidia NVreg_SoftEDIDs=0
NVreg_Mobile=0" workaround seems to affect mostly (only?) users of UXGA
(1600x1200) screens, and perhaps only those of a certain vintage at
that. If you look at the NVforums links I posted previously (or the
Livna bugzilla link) you'll see plenty of others reporting the same
problem. Also, just google "NVreg_SoftEDIDs=0 NVreg_Mobile=0".

> Are you sure that X doesn't automatically detect your LCD?

Very sure! Each time yum updates the Livna package of the nvidia driver
that line in question is removed from modprobe.conf, I forget that that
always happens, and on rebooting am faced with a garbled screen again.

> What happens if you use the driver package from NVIDIA, and DON'T pass
> the options to the nvidia driver?

I can't really show you (I was going to take a screenshot before I
realised that of course the screenshot would grab what should be being
displayed not what actually was). But without the option in
modprobe.conf the nvidia driver, whether installed from NVIDIA or from
Livna, garbles my display so that the top 10% of my desktop appears at
the bottom of my screen, and the right hand side of my desktop is
truncated by about 20% and replaced with vertical multicoloured lines.

Best, Darren

-- 
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D. D. Brierton            darren at dzr-web.com          www.dzr-web.com
       Trying is the first step towards failure (Homer Simpson)
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