Bug 99555

This code in __glXForceCurrent:

    if (cx->wait && (*cx->wait) (cx, cl, error))
        return NULL;

calls DRI2WaitSwap, which returns TRUE because there is a pending swap. I suspect something to deal with this went missing at a higher level at some point.

Xorg 1.18.3 and below works fine, xorg 1.18.4 fails.

Looking at the commits between 1.18.3 and 1.18.4 this commit seams pertain to the case: https://cgit.freedesktop.org/xorg/xserver/commit/?h=server-1.18-branch&id=54ba95861e5ae54051d3963e5e7ced7d69a6de7b

(In reply to diplosarus from comment #3)
> Looking at the commits between 1.18.3 and 1.18.4 this commit seams pertain
> to the case:
> https://cgit.freedesktop.org/xorg/xserver/commit/?h=server-1.18-
> branch&id=54ba95861e5ae54051d3963e5e7ced7d69a6de7b

Does reverting that commit fix it?

(In reply to Michel Dänzer from comment #4) 
> Does reverting that commit fix it?

No sadly not.

Also this bug Persists in 1.19.3

Can you bisect between 1.18.3 and 1.18.4?

I tested with xf86-video-ati-7.10.0-23-g733f606d. xorg-server-1.18.4 is good and xorg-server-1.19.0 is bad. Bisected and the result is:


7d33ab0f8c7958b205076f71e4b47c24aace77fd is the first bad commit
commit 7d33ab0f8c7958b205076f71e4b47c24aace77fd
Author: Adam Jackson <ajax@redhat.com>
Date:   Tue Jun 28 15:54:44 2016 -0400

    dri2: Don't make reference to noClientException

    noClientException is now never filled in with a meaningful value, it's
    always -1. The sole caller of this function disregards the error value
    in any case.

    Reviewed-by: Eric Anholt <eric@anholt.net>
    Signed-off-by: Adam Jackson <ajax@redhat.com>

:040000 040000 50ecf07fd43345192f937697193acbc91086e975 6d6494a0a06aed80c78491b758f7e35bf3059389 M      glx


Without 7d33ab0f8c7958b205076f71e4b47c24aace77fd, xorg-server-1.19.0 works but xorg-server-1.19.0-587-gbebcc8477 doesn't work. No X error but the following errors in dmesg:
[1654246.207734] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.212430] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.220569] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.220790] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.220880] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.236924] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.237176] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.237255] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.248485] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.248810] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.248960] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.265295] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.265866] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.266024] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.281986] radeon 0000:00:01.0: bo ffff90626cd73000 don't has a mapping in vm ffff90624f11d200
[1654246.992998] [drm:radeon_cs_parser_relocs [radeon]] *ERROR* gem object lookup failed 0x4c
[1654246.993025] [drm:radeon_cs_ioctl [radeon]] *ERROR* Failed to parse relocation -2!

I've hit this on Ubuntu 18.04 (xorg 1.19.6), modesetting driver. I have opened a bug over there in case someone on that side has time to investigate (https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1776447)

Interestingly, if I use VirtualGL as a true GLX proxy..

VGL_READBACK=sync LIBGL_ALWAYS_INDIRECT=1 VGL_DISPLAY=192.168.128.163:0 VGL_LOGO=1 vglrun +v /opt/VirtualGL/bin/glxspheres64

.. which I'm pretty sure it was never designed to do, things run successfully. So IGLX obviously isn't catastrophically broken ..

Created attachment 141901 [details]
Xorg log from iglx crash

Somewhere between 1.19 and version 1.20.1 this has goten worse. The Xorg server now crashes after LIBGL_ALWAYS_INDIRECT=1 glxgears. Log attached.

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