drm/i915: Support for ns2501-DVO

This patch adds support for the ns2501 DVO, found in some older Fujitsu/Siemens Labtops.
It is in the state of "works for me".
Includes now proper DPMS support. Includes switching between resolutions -
from 640x480 to 1024x768.
Currently assumes that the native display resolution is 1024x768.

The ns2501 seems to be rather critical - if the output PLL is not
running, the chip doesn't seem to be clocked and then doesn't react
on i2c messages. Thus, a quick'n-dirty trick ensures that the DVO
is active before submitting any i2c messages to it. This is
probably to be reviewed.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=17902
Signed-off-by: Thomas Richter <thor@math.tu-berlin.de>
[danvet: fixup whitespace fail.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f8c2aa1ec27a..93d9934ba328 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1428,8 +1428,10 @@ static void assert_pch_ports_disabled(struct drm_i915_private *dev_priv,
  * protect mechanism may be enabled.
  *
  * Note!  This is for pre-ILK only.
+ *
+ * Unfortunately needed by dvo_ns2501 since the dvo depends on it running.
  */
-static void intel_enable_pll(struct drm_i915_private *dev_priv, enum pipe pipe)
+void intel_enable_pll(struct drm_i915_private *dev_priv, enum pipe pipe)
 {
         int reg;
         u32 val;