BLack Screen while running X11 on /dev/fb1

umang gupta umang.ece at gmail.com
Tue Dec 14 02:33:16 PST 2010


Michel ,

I checked fbset output , its same in both cases and its :

mode "240x320-60"
    # D: 4.608 MHz, H: 19.200 kHz, V: 60.000 Hz
    geometry 240 320 240 320 32
    timings 217013 0 0 0 0 0 0
    rgba 8/16,8/8,8/0,8/24
endmode

Frame buffer device information:
    Name        : DISP3 FG
    Address     : 0x95000000
    Size        : 460800
    Type        : PACKED PIXELS
    Visual      : TRUECOLOR
    XPanStep    : 1
    YPanStep    : 1
    YWrapStep   : 0
    LineLength  : 960
    Accelerator : No

When I am using X11 on fb0 , fbset -i -fb /dev/fb0 gives me as

mode "800x480-59"
    # D: 30.303 MHz, H: 30.985 kHz, V: 59.018 Hz
    geometry 800 480 800 480 32
    timings 33000 0 50 25 10 128 10
    rgba 8/16,8/8,8/0,8/24
endmode

Frame buffer device information:
    Name        : DISP3 BG
    Address     : 0xae000000
    Size        : 33554432
    Type        : PACKED PIXELS
    Visual      : TRUECOLOR
    XPanStep    : 1
    YPanStep    : 1
    YWrapStep   : 0
    LineLength  : 3200
    Accelerator : No

Will this information help you to gain some pointers ?



Thanks ;
Umang Gupta


2010/12/14 Michel Dänzer <michel at daenzer.net>

> On Die, 2010-12-14 at 12:31 +0530, umang gupta wrote:
> >
> > I planned to run my X11 on 2nd framebuffer device /dev/fb1  in place
> > of fb0 . I have enabled both nodes in kernel and hence I have /dev/fb0
> > and /dev/fb1 on board  .
> > I created a conf file   22-xorg-fb1.conf
> > in /etc/X11/xorg.conf.d/ ..that I am attaching here .
> >
> > When I started X by running startx , I get a black screen . . I got
> > logs as Xfb1.log .
> >
> > Now I replace conf file with 22-xorg-fb0.conf that access fb0 .. I got
> > X11 seen on screen .  Logs received as Xfb0.log ..
> >
> > Now I kill X , again uses /dev/fb1 , run startx , it brings X11
> > up ...
> >
> >
> > I am not getting why , while using fb1  first time , I am getting
> > black screen ?
>
> Is there any difference in Xorg.0.log or the output of
>
>        fbset -i -fb /dev/fb1
>
> between the unsuccessful and successful attempts, or does something
> appear in the dmesg output between them? ...
>
>
> --
> Earthling Michel Dänzer           |                http://www.vmware.com
> Libre software enthusiast         |          Debian, X and DRI developer
>
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