[Mesa-dev] [Bug 40437] New: libGL should give some indication when DRI2 fails

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=40437

           Summary: libGL should give some indication when DRI2 fails
           Product: Mesa
           Version: 7.11
          Platform: All
               URL: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=63961
                    7
        OS/Version: All
            Status: NEW
          Severity: minor
          Priority: low
         Component: GLX
        AssignedTo: mesa-dev at lists.freedesktop.org
        ReportedBy: adeason+freedesktop at dson.org


See Debian bug 639617. Currently libGL fails pretty silently if DRI2 isn't
enabled on the X server:

$ LIBGL_DEBUG=verbose glxinfo -b
libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/r300_dri.so
libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/r300_dri.so
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 4, (OK)
drmOpenByBusid: Searching for BusID pci:0000:01:00.0
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 4, (OK)
drmOpenByBusid: drmOpenMinor returns 4
drmOpenByBusid: Interface 1.4 failed, trying 1.1
drmOpenByBusid: drmGetBusid reports pci:0000:01:00.0
libGL error: Calling driver entry point failedlibGL error: reverting to
software direct rendering
libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/swrast_dri.so
libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/swrast_dri.so
33

That "entry point failed" is because the installed r300_dri.so is the Gallium
driver, and doesn't support legacy DRI. So libGL tried to load DRI2, failed,
and fell back to DRI, which fails in r300_dri.so. Attached is a patch (modifies
libGL, and the *_dri.so drivers) to print out some more info when this happens,
which would have saved me some time in figuring out what was going on. With
this applied, I get this output (this is with 7.11-4 in Debian):

$ LIBGL_DEBUG=verbose /usr/bin/glxinfo -b
libGL: screen 0 does not appear to be DRI2 capable
libGL: XF86DRIGetClientDriverName: 5.3.0 r300 (screen 0)
libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/r300_dri.so
libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/r300_dri.so
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 4, (OK)
drmOpenByBusid: Searching for BusID pci:0000:01:00.0
drmOpenDevice: node name is /dev/dri/card0
drmOpenDevice: open result is 4, (OK)
drmOpenByBusid: drmOpenMinor returns 4
drmOpenByBusid: Interface 1.4 failed, trying 1.1
drmOpenByBusid: drmGetBusid reports pci:0000:01:00.0
libGL: driver does not support DRI1
libGL error: Calling driver entry point failedlibGL error: reverting to
software direct rendering
libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/swrast_dri.so
libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/swrast_dri.so
33

I don't know how you feel about whether there should be more/less messages
there, etc, but what's there is enough for me.

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