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Description of problem: it supports VGA&DP on the planar,there is no 1600x1200 resolution available when connecting the DP port. Version-Release number of selected component (if applicable): How reproducible: connect the DP of the planar, there is only Steps to Reproduce: 1: Install RHEL 6.0 64bit with OB DP (Dell 2408 or HP LP2475w) 2: Start X window 3: System-->Preferences-->Display-->Resolution 4: There are ONLY 4 resolutions.(640x480/800x600/1024x768/1280x1024) 5: Change to D-sub,the max resolution is 1600x1200 Actual results: when connecting to the DP port,there is no 1600x1200 resolution available in the list. Expected results: when connecting to the DP port,there is a same resolution list as connecting VGA port. Additional info: kernel:2.6.32-71.el6.x86_64 Intel Sandy Bridge & Cougar Point Based Platforms
Created attachment 474915 [details] DP port, no 1600x1200
This request was evaluated by Red Hat Product Management for inclusion in the current release of Red Hat Enterprise Linux. Because the affected component is not scheduled to be updated in the current release, Red Hat is unfortunately unable to address this request at this time. Red Hat invites you to ask your support representative to propose this request, if appropriate and relevant, in the next release of Red Hat Enterprise Linux. If you would like it considered as an exception in the current release, please ask your support representative.
This is expected. DP->VGA converters typically only have 2 lanes wired, and thus have a maximum pixel clock of 144MHz for 8bpc, which is too low for any common 1600x1200 mode. This is fixable by dithering to 6bpc, and while a patch to achieve this has been posted upstream it is not yet merged. Moving to 6.3 radar.
Patch tested and working, devel ack for 6.3.
Should be fixed in 6.3.