I have a Lenovo x220 with a core i5 2520m processor and integrated Intel HD Graphics (can't seem to find a model number for the graphics chipset). I bought a DisplayPort to HDMI connector and have tried it with both my TV (Sony Bravia) and my monitor (Viewsonic VX2260wm) and I get different - but both broken - results.
With the TV the output isn't even recognised as connected. The only time it has ever worked is when updating the Intel HD graphics drivers on Windows 7 Professional (64-bit). I first noticed it when I updated the graphics and it worked upon reboot. I thought that had fixed it, but another reboot and it stopped working - no matter how many times I rebooted or tried to "detect" the display. If I uninstall the Intel drivers and re-install them I get the same result. It works once and never again. I find this part really odd, but cannot figure out what might cause it.
With the Viewsonic monitor I am also using the DisplayPort to HDMI adapter and this time it works... but the dimensions are not detected properly. So the monitor is detected and is supposedly use 1366x768, but the sides of the screen are cut off. It seems Windows thinks the monitor is wider than it is. I have the exact same behaviour in Ubuntu (11.04 and 11.10). Again, odd and I cannot figure out what might cause it. Interestingly if I change the resolution (in Windows or Ubuntu) to be lower (1080x900, I think) it works. Though it is somewhat stretched because the resolution is 16:10 rather than 16:9.
I have done a bunch of investigation and I noticed an article on Wikipedia about DisplayPort compatibility with HDMI . In that article is says:
"DisplayPort is capable of directly emitting single-link HDMI and DVI signals using Dual-mode DisplayPort...Dual-mode DisplayPort chipset detects the DVI or HDMI passive adapter and switches to DVI/HDMI mode...Dual-mode compatible ports are marked with the DP++ logo; most current DisplayPort graphics cards and monitors support this mode."
Could there be a problem with detecting that link? Is it not switching modes properly? This is the only thing I can figure out. There is a DP++ logo on the DisplayPort, so it must support this mode. Does anyone know of any such issues? I'm a bit desperate at this point. :-/