Apple

Hello,

I’m in the process of writing a simple tool that will allow users to dynamically switch between their existing monitor profiles and other luts. I’m running into the same stumbling block that the message below mentions, namely that IOServiceOpen is failing to open the IOFramebuffer service because the window server has exclusive access to it.

Are there other apis that should be used for accessing the graphic card’s gamma table? Any help you can provide would be appreciated.

Regards,

HP Duiker

Duiker Research

Referenced message can be found here:

http://lists.apple.com/archives/darwin-kernel/2005/Apr/msg00074.html

Text:

Hi Amit,

At 17:14 +0530 15/4/05, Amit Gupta wrote:

I am trying to execute the code written below.

Here IOServiceOpen is giving error   -536870203

Can any one tell the reason for this error.



There's documentation that describes how to interpret I/O Kit error codes.

<http://developer.apple.com/documentation/DeviceDrivers/Conceptual/AccessingHardware/AH_Handling_Errors/chapter_6_section_2.html>

In this case, -536870203 is 0xe00002c5, which indicates a system of

I/O Kit (0x38) and, within that, the common subsystem (0).  The error

value is that in <IOKit/IOReturn.h>, namely:

#define kIOReturnExclusiveAccess iokit_common_err(0x2c5)// exclusive access and
// device already open



There's documentation about this error code as well.

<http://developer.apple.com/documentation/DeviceDrivers/Conceptual/AccessingHardware/AH_Handling_Errors/chapter_6_section_3.html>

The Window Server has the IOFramebufferUserClient open exclusively, thus the reason for the error you are seeing.

What is it you are trying to do?

Cheers,

--

J-Sun Seng

Networking & Communications / Hardware

Developer Technical Support

Apple Computer, Inc.

#1 Infinite Loop

M/S: 303-2T