用libdrm读取linux下的DisplayPort DDC/CI

Question

我正在尝试从我的显示器读取DDC信息，它连接到我的笔记本电脑的DisplayPort链接上。

因此，我正在查找i2cdetect和i2cdump，但找不到它连接到/dev/i2c总线上。

我的下一步是通过libdrm进行访问，我已经设置了一个drmModeConnector，但是接下来会发生什么呢？

根据德卡德的回答，我试过

sudo i2cdetect -l
i2c-0   i2c         i915 gmbus ssc                      I2C adapter
i2c-1   i2c         i915 gmbus vga                      I2C adapter
i2c-2   i2c         i915 gmbus panel                    I2C adapter
i2c-3   i2c         i915 gmbus dpc                      I2C adapter
i2c-4   i2c         i915 gmbus dpb                      I2C adapter
i2c-5   i2c         i915 gmbus dpd                      I2C adapter
i2c-6   i2c         DPDDC-B                             I2C adapter
i2c-7   smbus       SMBus I801 adapter at efa0          SMBus adapter

这表明面板连接到i2c-2，DisplayPort连接到i2c-6。当我运行$ sudo get-edid -b 6时，这会导致：

$ sudo get-edid -b 6
2 potential busses found: 2 6
Only trying 6 as per your request.
Bus 6 doesn't really have an EDID...
Couldn't find an accessible EDID on this computer.
Attempting to use the classical VBE interface

    Performing real mode VBE call
    Interrupt 0x10 ax=0x4f00 bx=0x0 cx=0x0
    Function supported
    Call successful

    VBE version 300
    VBE string at 0x11100 "Intel(R) Sandybridge/Ivybridge Graphics Chipset Accelerated VGA BIOS"

VBE/DDC service about to be called
    Report DDC capabilities

    Performing real mode VBE call
    Interrupt 0x10 ax=0x4f15 bx=0x0 cx=0x0
    Function supported
    Call successful

    Monitor and video card combination does not support DDC1 transfers
    Monitor and video card combination supports DDC2 transfers
    0 seconds per 128 byte EDID block transfer
    Screen is not blanked during DDC transfer

Reading next EDID block

VBE/DDC service about to be called
    Read EDID

    Performing real mode VBE call
    Interrupt 0x10 ax=0x4f15 bx=0x1 cx=0x0
    Function supported
    Call failed

The EDID data should not be trusted as the VBE call failed
Looks like VBE was successful. Have a good day.

不过，谢谢你的帮助！

有人能给我一个提示或张贴一些教程吗？

非常感谢并致以良好的问候，

贝费多

Answer 1

试一试

sudo get-edid

使用VESA VBE DDC协议检索和解释监控程序规范的工具

有关更多信息，请参见此处：http://manpages.ubuntu.com/manpages/lucid/man1/get-edid.1.html

更新：

试试看

• http://sourceforge.net/projects/ddccontrol/
• https://launchpad.net/ubuntu/+source/ddccontrol/

此外，这可能会导致您找到一个解决方案：

https://unix.stackexchange.com/questions/114359/how-to-get-edid-for-a-single-monitor

Answer 2

使用来自get-edid的相同结果，显示我的HDMI监视器的EDID的唯一函数是xrandr --verbose。