What's exactly doing PLATFORM=ID option?
Short answer:
The PLATFORMS=ID switch is to specify which platform ID on your system you want to use.
It's only important if you have multiple OpenCL devices in your system, from different vendors (mixing AMD/ATI and
nVidia cards in one system, for example.)
If you only have one platform on your system, you don't have to specify it. If you have multiple platforms,
Phoenix will tell you that it is needed. So, don't worry about it.
Long answer:
OpenCL is a standard developed by Khronos.
The "core" of OpenCL was not created by AMD/ATI nor nVidia, although they probably contribute to its development.
The problem is that, even though OpenCL is common, AMD/ATI and nVidia have different ideas about how to go about
bridging the gap between OpenCL and GPU. AMD/ATI gets from OpenCL to raw GPU code in a different way from how
nVidia does it, which makes nVidia's version of OpenCL totally incompatible with AMD/ATI cards and vice versa.
This can cause a serious problem when there is a system with some nVidia and some AMD/ATI cards in it: One vendor's
version of OpenCL will not work with another vendor's card, so Khronos needed a way of making sure independent
versions could exist on the same system. Their solution was to use an "installable client driver" (ICD) for each vendor.
So, when you install both AMD/ATI's OpenCL and nVidia's OpenCL, they exist as separate "platforms." One accesses
the AMD/ATI cards, the other accesses the nVidia cards.
So .. any ideas how to use phoenix with the followin scheme:
first slot - 5870
second slot - 5970
cause Catalyst reports that second GPU on 5970 is disabled:
Primary Adapter
Graphics Card Manufacturer Powered by AMD
Graphics Chipset ATI Radeon HD 5800 Series
Device ID 6898
Vendor 1002
Subsystem ID 21E6
Subsystem Vendor ID 1458
Graphics Bus Capability PCI Express 2.0
Maximum Bus Setting PCI Express 2.0 x8
BIOS Version 012.019.000.008
BIOS Part Number 113-C00801-011
BIOS Date 2010/03/01
Memory Size 1024 MB
Memory Type GDDR5
Core Clock in MHz 950 MHz
Memory Clock in MHz 1250 MHz
Total Memory Bandwidth in GByte/s 160.0 GByte/s
Linked Adapter
Graphics Card Manufacturer Powered by AMD
Graphics Chipset ATI Radeon HD 5900 Series
Device ID 689C
Vendor 1002
Subsystem ID C000
Subsystem Vendor ID 174B
Graphics Bus Capability PCI Express 2.0
Maximum Bus Setting PCI Express 2.0 x8
BIOS Version 012.020.000.014
BIOS Part Number 113-C01OCS-AC1
BIOS Date 2010/05/30
Memory Size 1024 MB
Memory Type GDDR5
Core Clock in MHz 735 MHz
Memory Clock in MHz 1010 MHz
Total Memory Bandwidth in GByte/s 129.3 GByte/s
Disabled Adapter
Graphics Card Manufacturer Powered by AMD
Graphics Chipset ATI Radeon HD 5900 Series
Device ID 689C
Vendor 1002
Subsystem ID C000
Subsystem Vendor ID 174B
Graphics Bus Capability PCI Express 2.0
Maximum Bus Setting PCI Express 2.0 x8
BIOS Version 012.020.000.019
BIOS Part Number 113-C01OCM-AC1
BIOS Date 2010/05/30
Memory Size 1024 MB
Memory Type GDDR5
Core Clock in MHz 735 MHz
Memory Clock in MHz 1010 MHz
Total Memory Bandwidth in GByte/s 129.3 GByte/s
and no chance to start phoenix or pocblm with device # parameter since the only active is number 0. Second is the cpu.
