[PATCH 2/2] drm/i915/bxt: Fix sanity check for BIOS RC6 setup

Imre Deak
2016-06-29T16:13:58Z

BXT BIOS has two options related to GPU power management: "RC6(Render
Standby)" and "GT PM Support". The assumption so far was that disabling
either of these options would leave RC6 uninitialized. According to my
tests this isn't so: for a proper RC6 setup we only need the "GT PM
Support" option to be enabled while the "RC6" option only controls
whether RC6 is left enabled or not by BIOS. OTOH we were missing a few
checks to ensure a proper RC6 setup. Add these now and don't fail the
sanity check if RC6 is disabled. This fixes a problem where RC6 remains
disabled after reloading the driver, since we explicitly disable RC6
during unloading.

CC: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
drivers/gpu/drm/i915/i915_reg.h | 5 +++++
drivers/gpu/drm/i915/intel_pm.c | 19 ++++++++++++++-----
2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index c6bfbf8..92b4046 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7085,12 +7085,17 @@ enum {
#define GEN6_RC6pp_THRESHOLD _MMIO(0xA0C0)
#define GEN6_PMINTRMSK _MMIO(0xA168)
#define GEN8_PMINTR_REDIRECT_TO_NON_DISP (1<<31)
+#define GEN8_MISC_CTRL0 _MMIO(0xA180)
#define VLV_PWRDWNUPCTL _MMIO(0xA294)
#define GEN9_MEDIA_PG_IDLE_HYSTERESIS _MMIO(0xA0C4)
#define GEN9_RENDER_PG_IDLE_HYSTERESIS _MMIO(0xA0C8)
#define GEN9_PG_ENABLE _MMIO(0xA210)
#define GEN9_RENDER_PG_ENABLE (1<<0)
#define GEN9_MEDIA_PG_ENABLE (1<<1)
+#define GEN8_PUSHBUS_CONTROL _MMIO(0xA248)
+#define GEN8_PUSHBUS_ENABLE _MMIO(0xA250)
+#define GEN8_PUSHBUS_SHIFT _MMIO(0xA25C)
+

#define VLV_CHICKEN_3 _MMIO(VLV_DISPLAY_BASE + 0x7040C)
#define PIXEL_OVERLAP_CNT_MASK (3 << 30)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 5dce264..fe76991 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5015,11 +5015,20 @@ static bool bxt_check_bios_rc6_setup(struct drm_i915_private *dev_priv)
enable_rc6 = false;
}

- if (!(I915_READ(GEN6_RC_CONTROL) & (GEN6_RC_CTL_RC6_ENABLE |
- GEN6_RC_CTL_HW_ENABLE)) &&
- ((I915_READ(GEN6_RC_CONTROL) & GEN6_RC_CTL_HW_ENABLE) ||
- !(I915_READ(GEN6_RC_STATE) & RC6_STATE))) {
- DRM_DEBUG_DRIVER("HW/SW RC6 is not enabled by BIOS.\n");
+ if (!I915_READ(GEN8_PUSHBUS_CONTROL) ||
+ !I915_READ(GEN8_PUSHBUS_ENABLE) ||
+ !I915_READ(GEN8_PUSHBUS_SHIFT)) {
+ DRM_DEBUG_DRIVER("Pushbus not setup properly.\n");
+ enable_rc6 = false;
+ }
+
+ if (!I915_READ(GEN6_GFXPAUSE)) {
+ DRM_DEBUG_DRIVER("GFX pause not setup properly.\n");
+ enable_rc6 = false;
+ }
+
+ if (!I915_READ(GEN8_MISC_CTRL0)) {
+ DRM_DEBUG_DRIVER("GPM control not setup properly.\n");
enable_rc6 = false;
}

--
2.5.0