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Setting resolution via fbset/xrandr

Yegor Yefremov
Expert 2370 points
Other Parts Discussed in Thread: DA8XX

I'm trying to change resolution on my am335x based board. LCD interface is connected to sii9022 HDMI converter. Kernel: git://arago-project.org/git/projects/linux-am33x.git branch: lcd-fbset

When I try to switch resolution from 1024x768 to 800x600 I get a wrong picture on the monitor. Monitor itself reports proper resolution and frequency (the same values, as when I set this resolution at compile time in drivers/video/da8xx). fbset reports proper values too. As far as i understand X server still operates in 1024x768.

I tried xrandr, but after adding mode and trying to apply it I got following error:

Configure crtc 0 failed

Any idea how to change the mode?

Yegor

  • 0
    TI__Prodigy 635 points

    Hi,

    It seems issue is as you mentioned - X server is not aware of changed timings.

    With matrix, if done as follows,

    1. stop matrix

    2. change timings with fbset

    3. start matrix

    display is proper.

    But if I don't stop matrix before changing resolution, display is not proper, so here reason would be that matrix is going with timings when it was started.

    If you are able to change timings with X server fully aware of it, I hope you would be able to get proper display. People who are knowledgeable on X server may be able to help you on this.

    Regards

    Afzal

  • 0 in reply to Afzal MOHAMMED
    Expert 2370 points

    Hello Afzal,

    you're right. My problem was, that I've tried to change resolution and then restart xdm. In this case xdm used old settings. But if I stop xdm and the change resolution via fbset and start xdm, the resolution changes.

    As for xrandr, this patch should help https://patchwork.kernel.org/patch/1876741/. But I haven't tested the stuff myself.

    Regards,

    Yegor