Xfbdev fails with "no screens found"

Wed Apr 13 23:28:53 PDT 2011

On Apr 13, 2011 10:29 PM, "Dushara Jayasinghe" <
dushara.jayasinghe at hydrix.com> wrote:
>
> Hi Thanks for the reply.
>
> Somehow I stuffed up the post with all the relevant info. I've pasted it
here again:
>
> ----------------------------------- >8
----------------------------------------
> DISPLAY wasn't the issue. To cut a long story short... I needed to update
some stuff on buildroot.
>
> However, it's still not working properly. I had to add the attached patch
to get it to work with the frame buffer device I'm using. Xfbdev runs fine
now but when I execute xlogo, nothing is displayed on the screen. The part
of the screen gets 'cleared' so I know that it writes something to /dev/fb0.

>
> The output of fbset -i:
>
> # fbset -i
>
> mode "240x128-158"
> # D: 5.000 MHz, H: 20.325 kHz, V: 157.560 Hz
> geometry 240 128 240 128 1
> timings 200000 3 1 0 0 2 1
> rgba 0/0,0/0,0/0,0/0
> endmode
>
> Frame buffer device information:
> Name : DISP0 BG
> Address : 0x906b8000
> Size : 4096
> Type : PACKED PIXELS
> Visual : MONO01
> XPanStep : 1
> YPanStep : 1
> YWrapStep : 0
> LineLength : 32
> Accelerator : No
> #
>
> ----------------------------------- >8
----------------------------------------
>
> I'm using Xfbdev because, this is for an embedded product and I want to
keep things as small as possible.
>
> The framebuffer driver I'm using is for a monochrome LCD panel running on
an iMX.25 based system (I tweaked the driver supplied by Freescale to suite
our needs.
>
> Thanks.
> Dushara
>
> P.S. What is preferred on this ML top/bottom posts?
>
>
> On 14/04/2011 12:03 PM, zt.tmzt at gmail.com wrote:
>>
>>
>> Hi.
>> Could you explain in more detail what you are trying to do, include the
output of fbset on your hardware and what framebuffer driver you are using?
>>
>> Xfbdev is not a nested server, don't see how setting DISPLAY would help.
>>
>> If you can, please strace Xfbdev and include that as well. I assume an
IOCTL is failing though I don't see any detailed logs. Xfbdev is based on
the kdrive X server, it doesn't have the same configuration or logging as
Xorg servers do. Why do you need to use Xfbdev, does Xorg (fbdev driver) not
work?
>>
>> Thanks,
>> Timothy Meade
>> tmzt on #xorg and #xorg-users
>>
>> On Apr 13, 2011 7:50 PM, "Dushara Jayasinghe" <
dushara.jayasinghe at hydrix.com> wrote:
>> >
>> > Sorry reposting this coz I stuffed up the subject...
>> >
>> > On 13/04/2011 4:34 PM, Dushara Jayasinghe wrote:
>> >>
>> >>  On 12/04/2011 11:06 AM, xorg-devel-request at lists.x.org wrote:
>> >>>
>> >>> Date: Mon, 11 Apr 2011 21:55:27 +0200
>> >>> From: Abdoulaye Walsimou GAYE<awg at embtoolkit.org>
>> >>> Subject: Re: Xfbdev fails with "no screens found"
>> >>> To: xorg-devel at lists.x.org
>> >>> Message-ID:<4DA35CAF.1090708 at embtoolkit.org>
>> >>> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
>> >>>
>> >>> On 04/11/2011 10:01 AM, Dushara Jayasinghe wrote:
>> >>>>
>> >>>> Hi all,
>> >>>>
>> >>>> I'm trying to use Xfbdev on an embedded linux device with a
monochrom LCD display. However, the command returns the following error:
>> >>>>
>> >>>> Fatal server error:
>> >>>> no screens found
>> >>>>
>> >>>> Using xserver_xorg-server-1.7.5
>> >>>> with kdrive/fbdev
>> >>>
>> >>> Hello,
>> >>> does the following command line, before starting Xfbdev, fixes the
issue:
>> >>> export DISPLAY=:0
>> >>>
>> >>>
>> >>>
>> >>> _______________________________________________
>> >>> xorg-devel at lists.x.org: X.Org development
>> >>> Archives: http://lists.x.org/archives/xorg-devel
>> >>> Info: http://lists.x.org/mailman/listinfo/xorg-devel
>> >
>> >
>> > --
>> > Dushara Jayasinghe | Senior Software Engineer
>> > dushara.jayasinghe at hydrix.com | +61 3 8573 5221
>> > Hydrix: Our Expertise – Your Competitive Advantage
>> > www.hydrix.com | fax +61 3 9572 2686 | phone +61 3 8573 5299
>> >
>> > _______________________________________________
>> > xorg-devel at lists.x.org: X.Org development
>> > Archives: http://lists.x.org/archives/xorg-devel
>> > Info: http://lists.x.org/mailman/listinfo/xorg-devel
>
>
> --
> Dushara Jayasinghe | Senior Software Engineer
> dushara.jayasinghe at hydrix.com | +61 3 8573 5221
> Hydrix: Our Expertise – Your Competitive Advantage
> www.hydrix.com | fax +61 3 9572 2686 | phone +61 3 8573 5299

I believe bottom, I couldn't figure out which of the quoted messages to
reply to.

I don't believe the visual is getting setup right, I'm pretty sure this
going to need changes to the server though Keith or someone else on the list
might know for sure. You might do better with overlay support, or something
that supports a single bit depth. I also wonder if the rgba mask has
anything to do with it. I haven't looked at this code recently, but I'm
pretty sure it's using MI/FB to create a visual from the FBIO fixed
structure. You can try -screen parameter if you can figure out the right
one, but it will probably still try to set the config back to the fbdev and
fail. If somebody knows how to create a monochrome visual/root pixmap you
could modify the server to do that, or properly support the visual flags in
your fbset output.

--
Timothy Meade
tmzt on #xorg-devel on freenode
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.x.org/archives/xorg-devel/attachments/20110414/f65310e2/attachment.htm>