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[kmgl]

Hello,

I try to use DirectGMA but I cannot find the required extension: GL_AMD_bus_addressable_memory from glxinfo nor when using CodeXL.

I use the new APP-SDKv2.9.1 and fglrx-14.41 on the FirePro W5100. My OS is RHEL 6.6.

What am I missing?

Thank you,

KmgL

[chm · Accepted solution]

Hi,

the extension is only exposed if a PCIE Aperture that can be used for DirectGMA is enabled. This is not done by default. You need to run the following commands as root and reboot (restarting X is not enough):

aticonfig --set-pcs-val=MCIL,DMAOGLExtensionApertureMB,96

aticonfig --set-pcs-u32=KERNEL,InitialPhysicalUswcUsageSize,96

This will set the size of the aperture to 96 MB. The max that is currently supported is 128 MB. Now you should see the GL_AMD_bus_addressable_memory extension when calling glxinfo.

Chris

[kmgl]

Thank you very much. That worked. Do you know whether there is documentation around DirectGMA because I found only in the OpenCL Progragmming Guide v2.7 a tiny bit of information.