Hi everybody,
this is the first time that i write here, until now i have only read and applied your advices for the most common issues of BOINC, and i want to thank you for helping me. I have searched all around the forum but i haven't found a solution for my problem.
Last week i have updated fglrx drivers for AMD gpu, (i've an HD7770) with the update manager of linux (my distro is Mint 17 Cinnamon x64), and it was happened the disaster. I copy and paste some rows of the log:

gio 20 ago 2015 20:13:31 CEST |  | App version needs OpenCL but GPU doesn't support it
gio 20 ago 2015 20:13:31 CEST |  | App version needs OpenCL but GPU doesn't support it
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | Scheduler request completed: got 18 new tasks
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] App version uses non-existent ATI GPU
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] App version uses non-existent ATI GPU
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644177_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644183_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644182_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644181_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_nonmodfit_fast_15_3s_136_sim1Aug1_2_1437561602_10424849_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644180_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_nonmodfit_fast_15_3s_136_sim1Aug1_2_1437561602_10424848_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644179_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_nonmodfit_fast_15_3s_136_sim1Aug1_2_1437561602_10424847_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644178_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_nonmodfit_fast_15_3s_136_sim1Aug1_2_1437561602_10424846_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644171_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_nonmodfit_fast_15_3s_136_sim1Aug1_2_1437561602_10424845_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644176_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_nonmodfit_fast_15_3s_136_sim1Aug1_2_1437561602_10424844_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644175_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_nonmodfit_fast_15_3s_136_sim1Aug1_2_1437561602_10424843_0; aborting
gio 20 ago 2015 20:13:31 CEST | Milkyway@Home | [error] Missing coprocessor for task de_80_DR8_Rev_8_5_00004_1437561602_13644173_0; aborting

everything was working fine before this update, but now BOINC can't send works on GPU because "it doesn't support openCL" (but boinc sees the GPU and allows me to change the settings of its use).
I've tried to uninstall and reinstall both BOINC and fglrx driver, change fglrx with fgrlx-updates (also with x-server because i was, and i am, so desperate), reboot and pray and so on...but without positive results.
I still haven't the possibility to use my GPU and i ask you if there are some issues with the newest AMD driver for linux (i saw that in the change log is write something about the support for openCL 2.0).
Thank you for help me and sorry for my english.

Regards

Riccardo

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PC BOINC: Dell precision T7400, CPU: 2xIntel Xeon 5420 2.5GHz, 16GB DDR2 RAM, AMD Radeon HD7770 by asus
PC Game: CPU AMD A8-5600K 3.7GHz, 12GB DDR3 1333MHz, MoBo MSI A88XG45, AMD radeon HD7850 by XFX, 256GB OCZ Agility4+WD 2TB, PSU Corsair CX500

Could you copy+paste the first 20 or so lines from BOINC's Event Log. In other words, the part where BOINC lists what it has detected.

And then open terminal and run the following command:

cd /usr/lib/x86_64-linux-gnu/ && sudo ln -s libOpenCL.so.1 libOpenCL.so

Then restart BOINC and see if anything changed.

Hi Juha,
here there are the lines:

ven 21 ago 2015 08:22:15 CEST |  | Starting BOINC client version 7.2.42 for x86_64-pc-linux-gnu
ven 21 ago 2015 08:22:15 CEST |  | log flags: file_xfer, sched_ops, task
ven 21 ago 2015 08:22:15 CEST |  | Libraries: libcurl/7.35.0 OpenSSL/1.0.1f zlib/1.2.8 libidn/1.28 librtmp/2.3
ven 21 ago 2015 08:22:15 CEST |  | Data directory: /var/lib/boinc-client
ven 21 ago 2015 08:22:15 CEST |  | CAL: ATI GPU 0: AMD Radeon HD 7700 series (Capeverde) (CAL version 1.4.1848, 1024MB, 841MB available, 3744 GFLOPS peak)
ven 21 ago 2015 08:22:15 CEST |  | App version needs OpenCL but GPU doesn't support it
ven 21 ago 2015 08:22:15 CEST | Milkyway@Home | Application uses missing ATI GPU
ven 21 ago 2015 08:22:15 CEST |  | App version needs OpenCL but GPU doesn't support it
ven 21 ago 2015 08:22:15 CEST | Milkyway@Home | Application uses missing ATI GPU
ven 21 ago 2015 08:22:15 CEST |  | Host name: riccardo-Precision-WorkStation-T7400
ven 21 ago 2015 08:22:15 CEST |  | Processor: 8 GenuineIntel Intel(R) Xeon(R) CPU           E5420  @ 2.50GHz [Family 6 Model 23 Stepping 6]
ven 21 ago 2015 08:22:15 CEST |  | Processor features: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 lahf_lm dtherm tpr_shadow vnmi flexpriority
ven 21 ago 2015 08:22:15 CEST |  | OS: Linux: 3.13.0-24-generic
ven 21 ago 2015 08:22:15 CEST |  | Memory: 15.67 GB physical, 8.00 GB virtual
ven 21 ago 2015 08:22:15 CEST |  | Disk: 458.23 GB total, 415.13 GB free
ven 21 ago 2015 08:22:15 CEST |  | Local time is UTC +2 hours
ven 21 ago 2015 08:22:15 CEST |  | Config: GUI RPCs allowed from:
ven 21 ago 2015 08:22:15 CEST | Einstein@Home | URL http://einstein.phys.uwm.edu/; Computer ID 12009054; resource share 100
ven 21 ago 2015 08:22:15 CEST | Milkyway@Home | URL http://milkyway.cs.rpi.edu/milkyway/; Computer ID 590742; resource share 100
ven 21 ago 2015 08:22:15 CEST | SETI@home | URL http://setiathome.berkeley.edu/; Computer ID 7409486; resource share 100
ven 21 ago 2015 08:22:15 CEST | rosetta@home | URL http://boinc.bakerlab.org/rosetta/; Computer ID 2182509; resource share 100
ven 21 ago 2015 08:22:15 CEST | Asteroids@home | URL http://asteroidsathome.net/boinc/; Computer ID 122937; resource share 100
ven 21 ago 2015 08:22:15 CEST |  | No general preferences found - using defaults
ven 21 ago 2015 08:22:15 CEST |  | Reading preferences override file
ven 21 ago 2015 08:22:15 CEST |  | Preferences:
ven 21 ago 2015 08:22:15 CEST |  | max memory usage when active: 12837.44MB
ven 21 ago 2015 08:22:15 CEST |  | max memory usage when idle: 14442.12MB
ven 21 ago 2015 08:22:15 CEST |  | max disk usage: 406.71GB
ven 21 ago 2015 08:22:15 CEST |  | (to change preferences, visit a project web site or select Preferences in the Manager)
ven 21 ago 2015 08:22:15 CEST |  | gui_rpc_auth.cfg is empty - no GUI RPC password protection
ven 21 ago 2015 08:22:15 CEST |  | Not using a proxy
ven 21 ago 2015 08:22:15 CEST | rosetta@home | Sending scheduler request: To fetch work.
ven 21 ago 2015 08:22:15 CEST | rosetta@home | Requesting new tasks for ATI
ven 21 ago 2015 08:22:23 CEST | rosetta@home | Scheduler request completed: got 0 new tasks
ven 21 ago 2015 08:22:28 CEST | Einstein@Home | Sending scheduler request: To fetch work.
ven 21 ago 2015 08:22:28 CEST | Einstein@Home | Requesting new tasks for ATI
ven 21 ago 2015 08:22:31 CEST | Einstein@Home | Scheduler request completed: got 0 new tasks
ven 21 ago 2015 08:22:31 CEST | Einstein@Home | No work sent

I have typed the command and have restarted boinc but nothing has changed, it give mi the same error. I saw that i have only the libOpenCL.so and not the libOpenCL.so.1.

---

PC BOINC: Dell precision T7400, CPU: 2xIntel Xeon 5420 2.5GHz, 16GB DDR2 RAM, AMD Radeon HD7770 by asus
PC Game: CPU AMD A8-5600K 3.7GHz, 12GB DDR3 1333MHz, MoBo MSI A88XG45, AMD radeon HD7850 by XFX, 256GB OCZ Agility4+WD 2TB, PSU Corsair CX500

Wrong directory, sorry. For some reason Ubuntu and Debian have different fglrx packages and place the files in different directories.

This one should work better:

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

I have no words for thank you! i typed the command and now GPU is working!!
I ask you one last thing: what does the command line do? i'm curious and i like to know the meanings of what i type :)

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PC BOINC: Dell precision T7400, CPU: 2xIntel Xeon 5420 2.5GHz, 16GB DDR2 RAM, AMD Radeon HD7770 by asus
PC Game: CPU AMD A8-5600K 3.7GHz, 12GB DDR3 1333MHz, MoBo MSI A88XG45, AMD radeon HD7850 by XFX, 256GB OCZ Agility4+WD 2TB, PSU Corsair CX500

I ask you one last thing: what does the command line do? i'm curious and i like to know the meanings of what i type :)

Your problem is similar to this one here and Juha has provided a very neat one line command to create a symbolic link (in the correct directory) to the OpenCL library. (boinc needs to find this library to request OpenCL tasks).

I ask you one last thing: what does the command line do? i'm curious and i like to know the meanings of what i type :)

Your problem is similar to this one here and Juha has provided a very neat one line command to create a symbolic link (in the correct directory) to the OpenCL library. (boinc needs to find this library to request OpenCL tasks).

To elaborate on that, the symbolic link libOpenCL.so -> libOpenCL.so.1 used to be included in the Debian/Ubuntu/AMD fglrx packages but was removed some versions ago. The link is really used only when compiling OpenCL programs, not running them, so perhaps it shouldn't have been packaged in the first place.

The reason why this link is needed is because BOINC client looks for a library with name libOpenCL.so .

wrong button

Ok, understood, thank you again (both agentb and juha). I updated fglrx driver after a year since the last time, and probably this is the reason why i discorver only now this problem. Probably i had the 14.4 or .9 before the update. I restart my works in milky after 2 weeks of nothing (probably my gpu will be less happy than me now).
C ya guys!

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PC BOINC: Dell precision T7400, CPU: 2xIntel Xeon 5420 2.5GHz, 16GB DDR2 RAM, AMD Radeon HD7770 by asus
PC Game: CPU AMD A8-5600K 3.7GHz, 12GB DDR3 1333MHz, MoBo MSI A88XG45, AMD radeon HD7850 by XFX, 256GB OCZ Agility4+WD 2TB, PSU Corsair CX500