[PATCH] [Natty SRU] drm/i915: disable PCH ports if needed when disabling a CRTC

[Keng-Yu Lin]

SRU Justification

Impact: Not uable to switch to the externel output-only (e.g. VGA or HDMI) mode.
It causes flickering on the externally attached monitor. This bug is common on
many SandyBridge-based laptops.

Fix: Upstream patch to disable PCH ports if needed when disabling a CRTC.

Test case: I tested on Lenovo Zhaoyang E47 and two Dell SandyBridge-based laptops.

BugLink: http://bugs.launchpad.net/bugs/791752

This backport patch is not in 2.6.38.y because of its end-of-life.
For the reference, the patch helps LP#745112 too, though not perfectly.


Keng-Yu Lin (1):
  drm/i915: disable PCH ports if needed when disabling a CRTC

 drivers/gpu/drm/i915/i915_reg.h      |   15 ++++++++
 drivers/gpu/drm/i915/intel_display.c |   61 +++++++++++++++++++++++++++++----
 2 files changed, 68 insertions(+), 8 deletions(-)

-- 
1.7.4.1