Merge branch 'drm-fixes-3.17' of git:// into drm-fixes

- fix a backlight regression resulting in dark screen
- add a PX quirk to avoid a hang with runtime pm
- fix an init issue on the CIK compute rings
- fix IH ring buffer overflows gracefully

* 'drm-fixes-3.17' of git://
  drm/radeon/cik: use a separate counter for CP init timeout
  drm/radeon: add PX quirk for asus K53TK
  drm/radeon: add a backlight quirk for Amilo Xi 2550
  drm/radeon: add a module parameter for backlight control (v2)
  drm/radeon: Update IH_RB_RPTR register after each processed interrupt
  drm/radeon: Make IH ring overflow debugging output more useful
  drm/radeon: Clear RB_OVERFLOW bit earlier