On Wed, May 27, 2015 at 10:57:32AM -0500, Bruce Dubbs wrote: > Richard Melville wrote: > >I've just configured my latest kernel (4.0.3) to utilise KMS (thanks Ken) > >rather than the legacy vesafb, but of course this has created other > >problems. > > > >The upside is that the font size on the console looks good on my monitor > >(1440x900) and the backlight now switches itself off when required -- it > >must have been broken on vesafb. > > > >The downside is that the EDID information fed to the kernel appears to give > >the wrong screen size. Only about 60% of the width and height are used. > > > >Maybe there's something I've missed in the kernel config. I've now turned > >off all legacy frame buffer settings that I can find, but it's made no > >difference. > > > >My feeling is that the monitor EDID info is corrupt; it's a cheap and > >fairly old model of unknown origin. If this is the case then I need to > >build an EDID file and place it in /lib/firmware. But first I have to > >discover exactly what the setting are for my monitor. > > > >My questions are: has anybody successfully built a custom EDID file, and > >what is the best way to query the monitor for the settings? Normally I > >would use xrandr, but I don't have xorg (with its libraries) installed, and > >I don't need it. Can xrandr be installed standalone? I've found a couple > >of other tools on the web (read-edid and edid-rw) but I'm unfamiliar with > >them. > > > >Any help much appreciated, otherwise I'll plough on alone :-( > > I've never had to do anything like that, but my first step would be to try a > commercial distro and see if the same problem persists. I'd also take a > look at the Xorg log. > > -- Bruce > Those sound like good places to start - remember to backup grub.cfg so you can restore it after the distro is installed.
There seem to be *two* EDID config options which mention FIRMWARE in the kernel, but I'm not sure which I use (my server uses one, but not sure about my desktops), and if it really is corrupt then I doubt changing the config will help. There is a read-edid or parse-edid tool (lots of references if you google 'linux EDID'), but it seems to be used to get the right data from a working example of the same monitor. I did find a post which mentioned setting custom modelines : I guess using xrandr would be the least painful way to try that (and ctrl-alt-backspace if it goes bad : hope it doesn't trash the monitor). I also found an oldish post mentioning setting up a conf file for the monitor with options including Option "UseEDID" "FALSE" and also Horizsync and Vertrefresh ranges but I'm not sure if it worked. ĸen -- Nanny Ogg usually went to bed early. After all, she was an old lady. Sometimes she went to bed as early as 6 a.m. -- http://lists.linuxfromscratch.org/listinfo/blfs-support FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page
