For Haswell, on some of the early hardware revisions, it is possible to run into issues when RC6 state is enabled and when pipes change state. v2: add comment saying that this is for early revisions only. v3: beautify as suggested by Daniel Vetter. Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com> --- drivers/gpu/drm/i915/i915_reg.h | 5 +++++ drivers/gpu/drm/i915/intel_pm.c | 10 ++++++++++ 2 files changed, 15 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 9d5bf06..793a172 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -4516,4 +4516,9 @@ #define SFUSE_STRAP_DDIC_DETECTED (1<<1) #define SFUSE_STRAP_DDID_DETECTED (1<<0) +#define WM_DBG 0x45280 +#define WM_DBG_DISALLOW_MULTIPLE_LP (1<<0) +#define WM_DBG_DISALLOW_MAXFIFO (1<<1) +#define WM_DBG_DISALLOW_SPRITE (1<<2) + #endif /* _I915_REG_H_ */ diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index bdcb5bd..2f6630a 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3475,6 +3475,16 @@ static void haswell_init_clock_gating(struct drm_device *dev) /* WaDisable4x2SubspanOptimization */ I915_WRITE(CACHE_MODE_1, _MASKED_BIT_ENABLE(PIXEL_SUBSPAN_COLLECT_OPT_DISABLE)); + + /* XXX: This is a workaround for early silicon revisions and should be + * removed later. + */ + I915_WRITE(WM_DBG, + I915_READ(WM_DBG) | + WM_DBG_DISALLOW_MULTIPLE_LP | + WM_DBG_DISALLOW_SPRITE | + WM_DBG_DISALLOW_MAXFIFO); + } static void ivybridge_init_clock_gating(struct drm_device *dev) -- 1.7.11.1
