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3D APP run failed after add RandR support on imx6q

Question asked by LeviathanSteven on Jul 15, 2013
Branched to a new discussion


Recently, I am working on a imx6q based board. The software is ubuntu_oneiric_4.0.0.tgz and L3.0.35_4.0.0_130424_images_MX6.tar.gz.

Also I did the instructions on file xserver-xorg-video-imx-viv-3.0.35-4.0.0/Instructions_to_setup_X11_acceleration_on_Ubuntu.

Then I got the default X driver from /opt/freescale/pkgs/xserver-xorg-video-imx-viv-3.0.35-4.0.0.tar.gz on the LTIB environment, and found that we can not switch mode by command xrandr, such xrandr --output HDMI --mode 1280x720. Also if we run xrandr -q, there is only one mode printed.

So need to modify the X driver and to add the xrandr support.

I did the following modification:

1, In xf86OutputFuncsRec.get_modes,  I got HDMI's EDID from /sys/devices/platform/mxc_hdmi/edid and passed to X in order to get all the supported modes.

2, In xf86OutputFuncsRec.mode_set,  I used fb ioctl FBIOPUT_VSCREENINFO to set the new mode.

3, In DPMS API, I used blank or unblank to turn on or turn off the FB.

After that, it works well, after I run command xrandr -q, many modes have been printed out. Then I can  run command xrandr --output HDMI --mode 1280x720 to switch the current mode from 1920x1080 to 1280x720.

But if I run some 3D applications, such as glxgears and the attachment demo, it will always occur some errors, such as "segmentation fault". After GDB, I found the error will always happened when function  'eglSwapBuffers'  being executed. If I switch the mode back to 1920x1080, all the 3D applications will run normally.

Also I tried to add the following content to function xf86CrtcConfigFuncsRec.resize  to modify the window pixmap.


        /* Access the screen. */

        ScreenPtr pScreen = pScrn->pScreen;

        if (NULL == pScreen) {

                return FALSE;


        /* Access the screen pixmap */

        PixmapPtr pScreenPixmap = (*pScreen->GetScreenPixmap)(pScreen);

        if (NULL == pScreenPixmap) {



                return FALSE;


      pScrn->virtualX = width;

      pScrn->virtualY = height;

      pScrn->displayWidth = width;

        const int bytesPerPixel = (pScrn->bitsPerPixel + 7) / 8;

        const int stride = pScrn->displayWidth * bytesPerPixel;

        /* Resize the screen pixmap to new size */





                -1,                     /* same depth */

                -1,                     /* same bitsperpixel */

                stride,                 /* devKind = stride */

                NULL);                  /* same memory ptr */



        return TRUE;


But the screen will display abnormal after switching mode, and the 3D app will also run failed.

It seems that I need to update more information in the RANDR driver. For example, function DRIGetDrawableInfo will update more HW private information to the 3D apps, how to modify it?

Could anyone can give some suggestion? Thanks in advance.





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