When I boot my Thinkpad T410 in a docking station with the lid closed, the lvds panel remains blank even when this output is active. This happens up to and including 3.5-rc2.
I've determined that this happens because lvds isn't being initialized by the bios when I boot this way, and booting with lvds_channel_mode=2 fixes the issue. I see that there's logic in is_dual_link_lvds() intended to detect this situation, but it's failing because the T410 has the LVDS_PIPEB_SELECT bit set. The simple patch below fixes my machine by masking off this bit when determining whether or not lvds was initialized by the bios. I'm not sure though whether or not it's correct to expect that this bit might be set when lvds hasn't been initialized. The alternative seems to be quirking this machine as is done for some Macbooks. What is the correct solution? Thanks, Seth
