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Lukas Wunner authored
commit 3916e3fd upstream. Single channel LVDS maxes out at 112 MHz. The 15" pre-retina models shipped with 1440x900 (106 MHz) by default or 1680x1050 (119 MHz) as a BTO option, both versions used dual channel LVDS even though the smaller one would have fit into a single channel. Notes: Bug report showing that the MacBookPro8,2 with 1440x900 uses dual channel LVDS (this lead to it being hardcoded in intel_lvds.c by Daniel Vetter with commit 618563e3): https://bugzilla.kernel.org/show_bug.cgi?id=42842 If i915.lvds_channel_mode=2 is missing even though the machine needs it, every other vertical line is white and consequently, only the left half of the screen is visible (verified by myself on a MacBookPro9,1). Forum posting concerning a MacBookPro6,2 with 1440x900, author is using i915.lvds_channel_mode=2 on the kernel command line, proving that the machine uses dual channels: https://bbs.archlinux.org/viewtopic.php?id=185770 Chi Mei N154C6-L04 with 1440x900 is a replacement panel for all MacBook Pro "A1286" models, and that model number encompasses the MacBookPro6,2 / 8,2 / 9,1. Page 17 of the panel's datasheet shows it's driven with dual channel LVDS: http://www.ebay.com/itm/-/400690878560 http://www.everymac.com/ultimate-mac-lookup/?search_keywords=A1286 http://www.taopanel.com/chimei/datasheet/N154C6-L04.pdf Those three 15" models, MacBookPro6,2 / 8,2 / 9,1, are the only ones with i915 graphics and dual channel LVDS, so that list should be complete. And the 8,2 is already in intel_lvds.c. Possible motivation to use dual channel LVDS even on the 1440x900 models: Reduce the number of different parts, i.e. use identical logic boards and display cabling on both versions and the only differing component is the panel. Signed-off-by:
Lukas Wunner <lukas@wunner.de> Acked-by:
Jani Nikula <jani.nikula@intel.com> [Jani: included notes in the commit message for posterity] Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
15e76766
