[Oneiric] SRU: Ivybridge graphics fix for 3.0.x

Robert Hooker sarvatt at ubuntu.com
Tue Nov 8 20:46:34 UTC 2011

From: Robert Hooker <sarvatt at tangerine.buildd>

 == Oneiric SRU Justification ==

 This wil affect all users of Ivybridge on Oneiric when it releases.

 This patch fixes Ivy Bridge bringup on Oneiric after recent bios
 updates where gpu frequency scaling was enabled. It does not affect
 anything besides Ivy Bridge (covered by IS_GEN7, IS_GEN6 is sandybridge
 generation) in the code and has no way to regress other systems.
 Without this patch, i915 will fail to load like this

 [drm:init_status_page], render ring hws offset: 0x00000000
 [drm:init_ring_common] *ERROR* render ring initialization failed ctl 00000000 head 00000000 tail 00000000 start 00000000
 [drm:i915_driver_load] *ERROR* failed to init modeset

 vesafb will then load, and X will use the vesa driver with all kinds
 of corruption problems due to the partially initialized GPU. No public
 bug has been filed because it is unreleased hardware but it has been
 tested internally.

[Test Case]
 Boot to X on an Ivy Bridge system, which is not possible without this

[Regression Potential]
 None, this only affects generation 7 GPU's which are unreleased and
 covered by IS_GEN7 in the patch. No new code is added, only the
 enabling of already existing code used for Sandy Bridge on the newer

Jesse Barnes (1):
  drm/i915: enable ring freq scaling, RC6 and graphics turbo on Ivy
    Bridge v3

 drivers/gpu/drm/i915/i915_debugfs.c  |    2 +-
 drivers/gpu/drm/i915/intel_display.c |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

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