[PATCH 2/2] drm/i915/gtt: Don't check PPGTT presence on PPGTT-only platforms

Michał Winiarski
2019-07-02T11:32:22Z

We missed one place where we check PPGTT-only platform for PPGTT
presence. Let's remove it.
While I'm here let's assert that this particular code is never called on
pre-gen8 platforms.

References: 4bdafb9ddfa4 ("drm/i915: Remove i915.enable_ppgtt override")
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 35 +++++++++--------------------
1 file changed, 10 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 30e14eac47ac..9e76347e039e 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3047,31 +3047,14 @@ static void bdw_setup_private_ppat(struct drm_i915_private *dev_priv)
{
u64 pat;

- if (!HAS_PPGTT(dev_priv)) {
- /* Spec: "For GGTT, there is NO pat_sel[2:0] from the entry,
- * so RTL will always use the value corresponding to
- * pat_sel = 000".
- * So let's disable cache for GGTT to avoid screen corruptions.
- * MOCS still can be used though.
- * - System agent ggtt writes (i.e. cpu gtt mmaps) already work
- * before this patch, i.e. the same uncached + snooping access
- * like on gen6/7 seems to be in effect.
- * - So this just fixes blitter/render access. Again it looks
- * like it's not just uncached access, but uncached + snooping.
- * So we can still hold onto all our assumptions wrt cpu
- * clflushing on LLC machines.
- */
- pat = GEN8_PPAT(0, GEN8_PPAT_UC);
- } else {
- pat = GEN8_PPAT(0, GEN8_PPAT_WB | GEN8_PPAT_LLC) | /* for normal objects, no eLLC */
- GEN8_PPAT(1, GEN8_PPAT_WC | GEN8_PPAT_LLCELLC) | /* for something pointing to ptes? */
- GEN8_PPAT(2, GEN8_PPAT_WT | GEN8_PPAT_LLCELLC) | /* for scanout with eLLC */
- GEN8_PPAT(3, GEN8_PPAT_UC) | /* Uncached objects, mostly for scanout */
- GEN8_PPAT(4, GEN8_PPAT_WB | GEN8_PPAT_LLCELLC | GEN8_PPAT_AGE(0)) |
- GEN8_PPAT(5, GEN8_PPAT_WB | GEN8_PPAT_LLCELLC | GEN8_PPAT_AGE(1)) |
- GEN8_PPAT(6, GEN8_PPAT_WB | GEN8_PPAT_LLCELLC | GEN8_PPAT_AGE(2)) |
- GEN8_PPAT(7, GEN8_PPAT_WB | GEN8_PPAT_LLCELLC | GEN8_PPAT_AGE(3));
- }
+ pat = GEN8_PPAT(0, GEN8_PPAT_WB | GEN8_PPAT_LLC) | /* for normal objects, no eLLC */
+ GEN8_PPAT(1, GEN8_PPAT_WC | GEN8_PPAT_LLCELLC) | /* for something pointing to ptes? */
+ GEN8_PPAT(2, GEN8_PPAT_WT | GEN8_PPAT_LLCELLC) | /* for scanout with eLLC */
+ GEN8_PPAT(3, GEN8_PPAT_UC) | /* Uncached objects, mostly for scanout */
+ GEN8_PPAT(4, GEN8_PPAT_WB | GEN8_PPAT_LLCELLC | GEN8_PPAT_AGE(0)) |
+ GEN8_PPAT(5, GEN8_PPAT_WB | GEN8_PPAT_LLCELLC | GEN8_PPAT_AGE(1)) |
+ GEN8_PPAT(6, GEN8_PPAT_WB | GEN8_PPAT_LLCELLC | GEN8_PPAT_AGE(2)) |
+ GEN8_PPAT(7, GEN8_PPAT_WB | GEN8_PPAT_LLCELLC | GEN8_PPAT_AGE(3));

I915_WRITE(GEN8_PRIVATE_PAT_LO, lower_32_bits(pat));
I915_WRITE(GEN8_PRIVATE_PAT_HI, upper_32_bits(pat));
@@ -3123,6 +3106,8 @@ static void gen6_gmch_remove(struct i915_address_space *vm)

static void setup_private_pat(struct drm_i915_private *dev_priv)
{
+ GEM_BUG_ON(INTEL_GEN(dev_priv) < 8);
+
if (INTEL_GEN(dev_priv) >= 10)
cnl_setup_private_ppat(dev_priv);
else if (IS_CHERRYVIEW(dev_priv) || IS_GEN9_LP(dev_priv))
--
2.21.0