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.
Created attachment 50635 [details] [review] Add some debug about DRI2 failing and if a driver does not support DRI1
Please provide your Signed-off-by: Ideally, submit the patches to the mesa-dev mailing list with git send-email.
Patches pushed to Mesa Git, thanks.
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