OS: Chrome OS R61
Forked from internal bug b/62805287 which tracked a blinking display
on Chell after a canary update. 
The CL https://chromium-review.googlesource.com/#/c/545104/ was used
there as a stop-gap measure to get Chell back to a working display quickly. The CL discusses a better approach that involves upstream backports [1].
Opening this as a tracker bug for the proper backports and also cherry-picks to non-3.18 kernels. 



[1] Iafc259338820d  was the initial "Detect DELL DA200 dongle" CHROMIUM WA.
Suggested backports: 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9a86cda07af2c6 drm/i915/dp: reduce link M/N parameters
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b31e85eda38c Detect USB-C specific dongles before reducing M and N
+ dependencies