I have recently built a system using a AMD HD7990 wilth Ubuntu and it was not as simple as i had hoped. [a Monty Python Swamp Castle build. The first one sank into the swamp ... but the fourth]

This was my first experience with AMD.

In summary first build on Ubuntu 14.10 failed, and then gave up on 14.04.2 settling on 14.04.1 - and then gave up on the latest 14.12 release of AMD´s drivers it gave errors and shut downs and settled on AMD´s 14.9.
To get it working and stable there were some threads especially valuable to understand what the problems were.

How to from hashcat, not boinc, but crunches with OpenCL.

Ubuntu bug report Can't install FGLRX driver in Ubuntu 14.04.2

Several posts at EinsteinAtHome relating to AMD´s latest drivers including latest drivers

Two boinc forum threads, the current "No usable GPUs found"

and especially this now closed thread

No usable GPUs found. AMD Radeon HD6750 (could this be made sticky?) as being invaluable. -The information about the libraries and associated environment variable was very helpful.

The install had not created a libOpenCL.so library link. (the libOpenCL.so.1 file existed) so needed to create a link sudo ln -s /usr/lib/libOpenCL.so.1 libOpenCL.so this may not work for some, and a copy may need to be made. The thread offered a suggestion for an environment variable for boinc to find the library file. I added this line

LD_LIBRARY_PATH=/lib64:/usr/lib:/lib:/usr/local/lib

to /etc/defaults/boinc-client which started GPU tasks running.

Other OpenCL package installs from AMD (I think the dev package I read somewhere) may create the link, but this link should be sufficient.

A feature of the Ubuntu repo install of boinc is to auto-start (as user=boinc) AND recognize the GPUs and process GPU+CPU tasks unattended would not detect the GPU.

To start GPU tasks i had to - log into an X session, stop the boinc-client service, type an xhost command and restart boinc-client

To fix this and autostart with GPU tasks, (CPU tasks were always fine) i needed to modify the /etc/lightdm/lightdm.conf file to add

[SeatDefaults]
display-setup-script=/usr/bin/xhost +SI:userlocal:boinc

Which forces the xhost command to be run, unattended.

I could not trick xhost to run during init x session. (setting DISPLAY environment variable)

Hope this saves a few ubuntu build falling into the swamp!

Thanks to the various authors and help over at E@H, otherwise i would not have it crunching.

AMD have released a new driver 15.5 and so i had a chance to check over the detail (again on 14.04.1)

The install had not created a libOpenCL.so library link. (the libOpenCL.so.1 file existed) so needed to create a link

cd /usr/lib
sudo ln -s /usr/lib/libOpenCL.so.1 libOpenCL.so

this link may not work for some, and a copy may need to be made.

The thread offered a suggestion for an environment variable for boinc to find the library file. I added this line

sudo gedit /etc/defaults/boinc-client

and add

LD_LIBRARY_PATH=/lib64:/usr/lib:/lib:/usr/local/lib
export LD_LIBRARY_PATH

a point to look for in the message logs

If you see

04-Jun-2015 22:31:31 [---] Data directory: /var/lib/boinc-client
04-Jun-2015 22:31:31 [---] CAL: ATI GPU 0: AMD Radeon HD 7870/7950/7970/R9 280X 
series (Tahiti) (CAL version 1.4.1848, 3072MB, 2860MB available, 10752 GFLOPS peak)

Then boinc sees the GPU but can not find the OpenCL library.

04-Jun-2015 23:18:34 [---] Data directory: /var/lib/boinc-client
04-Jun-2015 23:18:34 [---] OpenCL: AMD/ATI GPU 0: Tahiti (driver version 1702.3 (VM), device version OpenCL 1.2 AMD-APP (1702.3), 2829MB, 2829MB available, 2688 GFLOPS peak)

Boinc now can find OpenCL.

apologies a typo to correct

[SeatDefaults]
display-setup-script=/usr/bin/xhost +SI:localuser:boinc


If you have the need to over / under clock the GPU, this is well worth looking at

AMDOverdriveCtrl

Greetings,

I would like to add a variation and solution..

I was using LinuxMint 14.04 and was crunching merrily with GPU on SETI and Einstein
on AMD/ATI HD7750.
Then, I went on vacation.
When I came back, I did an update and upgrade - an then BOINC said my openCL was not usable.

After reinstalling the drivers from packages (more info at bottom), I upgraded to Ubuntu Mate 15.04 and started over.

I installed with the PPA from:
ppa:costamagnagianfranco/locutusofborg-ppa

Still,
GPU not found.
clinfo said I had openCL for both the processor card and the GPU card.

I added
LD_LIBRARY_PATH=/lib64:/usr/lib:/lib:/usr/local/lib

I also did an xhost local:boinc
and
sudo aticonfig --initial=check

Hurray, the GPU crunches.

FYI
I did not build the AMD driver - but had installed the packages
fglrx-updates and fglrx-amdcccle-updates

FYI, I tried opening up permissions on the lib_openCL in /usr/lib
lrwxrwxrwx 1 0 0 14 Jun 26 01:19 libOpenCL.so -> libOpenCL.so.1
-rw-rw-rw- 1 0 0 27328 Apr 16 12:20 libOpenCL.so.1


Could it possibly be a problem when both CPU and GPU declare that they have OpenCL?

One other oddity in stderrgpudetect.txt; it said:
No protocol specified
Error! Fail to load fglrx kernel module! Maybe you can switch to root user to load kernel module directly

and stdoutgpudetect.txt said
Error: No root privilege. Please check with the system-admin.

I have no idea where the privilege problem happened - or if it is important.

Thanks for all of the above posts to guide me along...

Jay