On Wednesday 09 May 2007 09:07, Luming Yu wrote: > To use this patch, you need enable VIDEO_OUTPUT_CONTROL and ACPI_VIDEO. > After loading output.ko and video.ko, you would have > /sys/class/video_output and several device acpi_videoNum there. For > example, I got acpi_video0, acpi_video1,acpi_video2,and acpi_video3 > under /sys/class/video_output on my T40. > I can query the status of output device0 by running " cat > /sys/class/video_output/acpi_video0 > " The return value is defined in ACPI SPEC B.5.5 _DCS(Return the > Status of Output Device). Also you can turn off video1 and turn on > video0 by " echo 0 > acpi_video1; echo 0x80000000 > acpi_video0". > Please reference ACPI SPEC B.5.7 _DSS for the parameter definition. > Also please note that it may or may NOT works purely depending on if > your vendor providing correct ACPI video extension support in bios. > the driver output.ko and video.ko just works like a interface to > invoke BIOS. This is a step in the right direction, but nothing in a generic sysfs location should depend on bit encodings from the ACPI spec. eg. from user-space they should be something simple like 0 - disabled 1 - enabled on read, they should probably query _DCS, and decode its bit pattern so that again the user sees: 0 - disabled 1 - enabled I'll put this patch in the test tree now b/c I want folks to be able to test _DSS, so feel free to send an incremental patch on top of this one. thanks, -Len - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
