drm/i915: add hw state readout/checking for pipe_config

We need to be able to read out the hw state code for a bunch
of reasons:
- Correctly disabling boot-up/resume state.
- Pure paranoia.

Since not all of the pipe configuration is e.g. relevant for
fastboot (or at least we can allow some wiggle room in some
parameters, like the clocks), we need to add a strict_checking
parameter to intel_pipe_config_compare for fastboot.

For now intel_pipe_config_compare should be fully paranoid and
check everything that the hw state readout code supports. Which
for this infrastructure code is nothing.

I've gone a bit overboard with adding 3 get_pipe_config functions:
The ilk version will differ with the next patch, so it's not too
onerous.

v2: Don't check the hw config if the pipe is off, since an enabled,
but dpms off crtc will obviously have tons of difference with the hw
state.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index b8df39e37135..44fca0b69473 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -285,6 +285,7 @@ struct drm_i915_error_state {
 };
 
 struct intel_crtc_config;
+struct intel_crtc;
 
 struct drm_i915_display_funcs {
         bool (*fbc_enabled)(struct drm_device *dev);
@@ -298,6 +299,10 @@ struct drm_i915_display_funcs {
         void (*update_linetime_wm)(struct drm_device *dev, int pipe,
                                  struct drm_display_mode *mode);
         void (*modeset_global_resources)(struct drm_device *dev);
+        /* Returns the active state of the crtc, and if the crtc is active,
+         * fills out the pipe-config with the hw state. */
+        bool (*get_pipe_config)(struct intel_crtc *,
+                                struct intel_crtc_config *);
         int (*crtc_mode_set)(struct drm_crtc *crtc,
                              int x, int y,
                              struct drm_framebuffer *old_fb);