From b212f0a470eeb62a8eaa95f51b3cdbc457f687a8 Mon Sep 17 00:00:00 2001 From: Tvrtko Ursulin Date: Mon, 3 Sep 2018 12:30:07 +0100 Subject: [PATCH] drm/i915/icl: Fix context RPCS programming There are two issues with the current RPCS programming for Icelake: Expansion of the slice count bitfield has been missed, as well as the required programming workaround for the subslice count bitfield size limitation. 1) Bitfield width for configuring the active slice count has grown so we need to program the GEN8_R_PWR_CLK_STATE accordingly. Current code was always requesting eight times the number of slices (due writing to a bitfield starting three bits higher than it should). These requests were luckily a) capped by the hardware to the available number of slices, and b) we haven't yet exported the code to ask for reduced slice configurations. Due both of the above there was no impact from this incorrect programming but we should still fix it. 2) Due subslice count bitfield being only three bits wide and furthermore capped to a maximum documented value of four, special programming workaround is needed to enable more than four subslices. With this programming driver has to consider the GT configuration as 2x4x8, while the hardware internally translates this to 1x8x8. A limitation stemming from this is that either a subslice count between one and four can be selected, or a subslice count equaling the total number of subslices in all selected slices. In other words, odd subslice counts greater than four are impossible, as are odd subslice counts greater than a single slice subslice count. This also had no impact in the current code base due breakage from 1) always reqesting more than one slice. While fixing this we also add some asserts to flag up any future bitfield overflows. v2: * Use a local in all branches for clarity. (Lionel) Signed-off-by: Tvrtko Ursulin Bspec: 12247 Reported-by: tony.ye@intel.com Suggested-by: Lionel Landwerlin Cc: Lionel Landwerlin Cc: tony.ye@intel.com Cc: Mika Kuoppala Reviewed-by: Lionel Landwerlin Link: https://patchwork.freedesktop.org/patch/msgid/20180903113007.2643-1-tvrtko.ursulin@linux.intel.com --- drivers/gpu/drm/i915/i915_reg.h | 2 + drivers/gpu/drm/i915/intel_lrc.c | 87 +++++++++++++++++++++++++++----- 2 files changed, 76 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index f2321785cbd6..09bc8e730ee1 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -344,6 +344,8 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg) #define GEN8_RPCS_S_CNT_ENABLE (1 << 18) #define GEN8_RPCS_S_CNT_SHIFT 15 #define GEN8_RPCS_S_CNT_MASK (0x7 << GEN8_RPCS_S_CNT_SHIFT) +#define GEN11_RPCS_S_CNT_SHIFT 12 +#define GEN11_RPCS_S_CNT_MASK (0x3f << GEN11_RPCS_S_CNT_SHIFT) #define GEN8_RPCS_SS_CNT_ENABLE (1 << 11) #define GEN8_RPCS_SS_CNT_SHIFT 8 #define GEN8_RPCS_SS_CNT_MASK (0x7 << GEN8_RPCS_SS_CNT_SHIFT) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index f8ceb9c99dd6..def467c2451b 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -2480,6 +2480,9 @@ int logical_xcs_ring_init(struct intel_engine_cs *engine) static u32 make_rpcs(struct drm_i915_private *dev_priv) { + bool subslice_pg = INTEL_INFO(dev_priv)->sseu.has_subslice_pg; + u8 slices = hweight8(INTEL_INFO(dev_priv)->sseu.slice_mask); + u8 subslices = hweight8(INTEL_INFO(dev_priv)->sseu.subslice_mask[0]); u32 rpcs = 0; /* @@ -2489,6 +2492,38 @@ make_rpcs(struct drm_i915_private *dev_priv) if (INTEL_GEN(dev_priv) < 9) return 0; + /* + * Since the SScount bitfield in GEN8_R_PWR_CLK_STATE is only three bits + * wide and Icelake has up to eight subslices, specfial programming is + * needed in order to correctly enable all subslices. + * + * According to documentation software must consider the configuration + * as 2x4x8 and hardware will translate this to 1x8x8. + * + * Furthemore, even though SScount is three bits, maximum documented + * value for it is four. From this some rules/restrictions follow: + * + * 1. + * If enabled subslice count is greater than four, two whole slices must + * be enabled instead. + * + * 2. + * When more than one slice is enabled, hardware ignores the subslice + * count altogether. + * + * From these restrictions it follows that it is not possible to enable + * a count of subslices between the SScount maximum of four restriction, + * and the maximum available number on a particular SKU. Either all + * subslices are enabled, or a count between one and four on the first + * slice. + */ + if (IS_GEN11(dev_priv) && slices == 1 && subslices >= 4) { + GEM_BUG_ON(subslices & 1); + + subslice_pg = false; + slices *= 2; + } + /* * Starting in Gen9, render power gating can leave * slice/subslice/EU in a partially enabled state. We @@ -2496,24 +2531,50 @@ make_rpcs(struct drm_i915_private *dev_priv) * enablement. */ if (INTEL_INFO(dev_priv)->sseu.has_slice_pg) { - rpcs |= GEN8_RPCS_S_CNT_ENABLE; - rpcs |= hweight8(INTEL_INFO(dev_priv)->sseu.slice_mask) << - GEN8_RPCS_S_CNT_SHIFT; - rpcs |= GEN8_RPCS_ENABLE; + u32 mask, val = slices; + + if (INTEL_GEN(dev_priv) >= 11) { + mask = GEN11_RPCS_S_CNT_MASK; + val <<= GEN11_RPCS_S_CNT_SHIFT; + } else { + mask = GEN8_RPCS_S_CNT_MASK; + val <<= GEN8_RPCS_S_CNT_SHIFT; + } + + GEM_BUG_ON(val & ~mask); + val &= mask; + + rpcs |= GEN8_RPCS_ENABLE | GEN8_RPCS_S_CNT_ENABLE | val; } - if (INTEL_INFO(dev_priv)->sseu.has_subslice_pg) { - rpcs |= GEN8_RPCS_SS_CNT_ENABLE; - rpcs |= hweight8(INTEL_INFO(dev_priv)->sseu.subslice_mask[0]) << - GEN8_RPCS_SS_CNT_SHIFT; - rpcs |= GEN8_RPCS_ENABLE; + if (subslice_pg) { + u32 val = subslices; + + val <<= GEN8_RPCS_SS_CNT_SHIFT; + + GEM_BUG_ON(val & ~GEN8_RPCS_SS_CNT_MASK); + val &= GEN8_RPCS_SS_CNT_MASK; + + rpcs |= GEN8_RPCS_ENABLE | GEN8_RPCS_SS_CNT_ENABLE | val; } if (INTEL_INFO(dev_priv)->sseu.has_eu_pg) { - rpcs |= INTEL_INFO(dev_priv)->sseu.eu_per_subslice << - GEN8_RPCS_EU_MIN_SHIFT; - rpcs |= INTEL_INFO(dev_priv)->sseu.eu_per_subslice << - GEN8_RPCS_EU_MAX_SHIFT; + u32 val; + + val = INTEL_INFO(dev_priv)->sseu.eu_per_subslice << + GEN8_RPCS_EU_MIN_SHIFT; + GEM_BUG_ON(val & ~GEN8_RPCS_EU_MIN_MASK); + val &= GEN8_RPCS_EU_MIN_MASK; + + rpcs |= val; + + val = INTEL_INFO(dev_priv)->sseu.eu_per_subslice << + GEN8_RPCS_EU_MAX_SHIFT; + GEM_BUG_ON(val & ~GEN8_RPCS_EU_MAX_MASK); + val &= GEN8_RPCS_EU_MAX_MASK; + + rpcs |= val; + rpcs |= GEN8_RPCS_ENABLE; } -- 2.30.2