drm/dp: move hw_mutex up the call stack

1) don't let other threads trying to bang on aux channel interrupt the
defer timeout/logic
2) don't let other threads interrupt the i2c over aux logic

Technically, according to people who actually have the DP spec, this
should not be required.  In practice, it makes some troublesome Dell
monitor (and perhaps others) work, so probably a case of "It's compliant
if it works with windows" on the hw vendor's part..

v2: rebased to come before DPCD/AUX logging patch for easier backport
to stable branches.

Reported-by: Dave Wysochanski <[email protected]>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1274157
Cc: [email protected]
Signed-off-by: Rob Clark <[email protected]>
Reviewed-by: Ville Syrjälä <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>

0 files changed, 0 insertions, 0 deletions