Commit df8dc97cd17 (drm/nouveau/kms/nv50: use drm core i2c-over-aux algorithm) switched things over to the drm algo. Unfortunately it generates address-only transactions. Prior to GF119, the hardware had no support for such things, and GF119+ the nouveau code did not handle these properly. The result of this bug is that EDID doesn't make it over for DP (and eDP) screens, which in turn wreaks all sorts of havoc. There have been lots of reports on IRC, a few on mailing lists, and also: https://bugs.freedesktop.org/show_bug.cgi?id=102528 Commit 13a86519202 (drm/nouveau/i2c/gf119-: add support for address-only transactions) fixes the nouveau support for such transactions on GF119+ and flips things back over to the custom algo for earlier chips. Please include into the next v4.12.x release: commit 13a86519202c5d119d83640d6f781f3181205d2c Author: Ben Skeggs <bskeggs@xxxxxxxxxx> Date: Wed Jul 19 16:49:59 2017 +1000 drm/nouveau/i2c/gf119-: add support for address-only transactions Since switching the I2C-over-AUX helpers, there have been regressions on some display combinations due to us not having support for "address only" transactions. This commits enables support for them for GF119 and newer. Earlier GPUs have been reverted to a custom I2C-over-AUX algorithm. Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>