I have just installed a Sapphire AMD Radeon R7 240 graphics card on my desktop system, which runs OK except that invoking
Kinfocenter->Graphical Information->OpenGL
appears to crash the graphics driver.  The symptom is that the session restarts with a large number (8) of crash warnings reported by Drkonqi, the KDE Crash Handler.  None of these error messages seems to be very informative, however here is part of the output of the 1st one:
Details:
Executable: akonadi_maildispatcher_agent PID: 4234 Signal: Aborted (6) Time: 11/01/14 10:18:16 PM

The system is Fedora-20 with all upgrades running on a 4 CPU x86_64 system. 

The graphics hardware identifies itself as:
$ lspci | grep -i vga
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Oland PRO [Radeon R7 240]
The video drivers are:
$ lsmod | grep radeon
radeon               1415819  3
i2c_algo_bit           13257  1 radeon
ttm                    80807  1 radeon
drm_kms_helper         58041  1 radeon
drm                   291361  6 ttm,drm_kms_helper,radeon
i2c_core               55486  7 drm,i2c_piix4,drm_kms_helper,i2c_algo_bit,v4l2_common,radeon,videodev
Before I install the proprietary drivers from AMD, I'd like to see if the open source drivers can be got to work.  Any advice is welcome.

Thanks