[pull request][oneiric] Fixes for i915 PCH refclk code

Herton Ronaldo Krzesinski herton.krzesinski at canonical.com
Wed Dec 7 12:29:57 UTC 2011

On Tue, Dec 06, 2011 at 04:44:39PM -0600, Seth Forshee wrote:
> BugLink: http://bugs.launchpad.net/bugs/614238
> These patches address a long-standing problem that causes VGA output
> problems on some machines. These patches went into Linus's tree during
> the 3.2 merge window, but I've been sitting on them a while as all
> previous attempts to fix the problem had to be reverted due to
> regressions on other hardware. Things are looking better this time
> around, so please consider these backports for oneiric.
> == SRU Justification ==
> Impact: On some machines with an Ibex Peak PCH, SSC will be enabled on
> the clock source used for analog outputs. This results in poor quality
> output (described as "wavy") on the external display.
> Fix: A series of upstream backports to the i915 driver. With these
> backports, the driver will check for the existence of a CK505 clock
> source, and if present this is used as the reference clock for analog
> outputs so that SSC can remain enabled. Otherwise SSC is disabled. The
> PCH refclk update code is also split out so that it can be called from
> additional locations where the refclks should be updated.
> Test Case: Running with backports on an affected system will fix quality
> issues on VGA outputs. Verified for oneiric on LP #614238.
> The following changes since commit 9b17787b269086b6556df3ff25f1421a5111131c:
>   UBUNTU: Ubuntu-3.0.0-14.23 (2011-11-21 15:59:26 -0200)
> are available in the git repository at:
>   git://kernel.ubuntu.com/sforshee/ubuntu-oneiric.git lp614238
> Jesse Barnes (1):
>       drm/i915: split out PCH refclk update code
> Keith Packard (7):
>       drv/i915: Pull display_clock_mode out of VBT table
>       drm/i915: Document a few more BDB_GENERAL_FEATURES bits from PCH BIOS
>       drm/i915: Allow SSC parameter to override VBT value
>       drm/i915: Fix PCH SSC reference clock settings
>       drm/i915: Use CK505 as non-SSC source where available
>       drm/i915: All PCH refclks are 120MHz
>       drm/i915: Initialize PCH refclks at modeset init time
> Thomas Jarosch (1):
>       drm/i915: Fix wrong initializer for "locked" variable in assert_panel_unlocked
>  drivers/gpu/drm/i915/i915_drv.c      |    8 ++-
>  drivers/gpu/drm/i915/i915_drv.h      |    2 +
>  drivers/gpu/drm/i915/intel_bios.c    |    7 ++
>  drivers/gpu/drm/i915/intel_bios.h    |    9 ++-
>  drivers/gpu/drm/i915/intel_display.c |  183 +++++++++++++++++++++++----------
>  5 files changed, 150 insertions(+), 59 deletions(-)

The backport looks ok. It seems cherry-picking the simple
"drm/i915: Use DRM_DEBUG_KMS for all messages in intel_bios.c",
belonging to the same series, would allow cherry-picking cleanly
abd06860185fc613776adae792772e076d77caf2, wouldn't change the end
result anyway. And looks like a bug with a lot of "heat", so:

Acked-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>


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