From 2d4c6c348fd695e0cdc037a5fa3eeb88a75e75af Mon Sep 17 00:00:00 2001
From: Cooper Chiou <cooper.chiou@intel.com>
Date: Mon, 25 Oct 2021 12:26:23 +0800
Subject: drm/i915: Enable WaProgramMgsrForCorrectSliceSpecificMmioReads for
Gen9
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Git-commit: c7d561cfcf8661ef02218655c923a0eadbbd7520
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
This implements WaProgramMgsrForCorrectSliceSpecificMmioReads which
was omitted by mistake from Gen9 documentation, while it is actually
applicable to fused off parts.
Workaround consists of making sure MCR packet control register is
programmed to point to enabled slice/subslice pair before doing any
MMIO reads from the affected registers.
Failure do to this can result in complete system hangs when running
certain workloads. Two known cases which can cause system hangs are:
1. "test_basic progvar_prog_scope_uninit" test which is part of
Khronos OpenCL conformance suite
(https://github.com/KhronosGroup/OpenCL-CTS) with the Intel
OpenCL driver (https://github.com/intel/compute-runtime).
2. VP8 media hardware encoding using the full-feature build of the
Intel media-driver (https://github.com/intel/media-driver) and
ffmpeg.
For the former case patch was verified to fix the hard system hang
when executing the OCL test on Intel Pentium CPU 6405U which contains
fused off GT1 graphics.
Reference: HSD#1508045018,1405586840, BSID#0575
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: William Tseng <william.tseng@intel.com>
Cc: Shawn C Lee <shawn.c.lee@intel.com>
Cc: Pawel Wilma <pawel.wilma@intel.com>
Signed-off-by: Cooper Chiou <cooper.chiou@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211025042623.3876-1-cooper.chiou@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gt/intel_workarounds.c | 41 +++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
index 2400d6423ba5..8bedffe4ac8a 100644
--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
@@ -870,11 +870,52 @@ hsw_gt_workarounds_init(struct intel_gt *gt, struct i915_wa_list *wal)
wa_write_clr(wal, GEN7_FF_THREAD_MODE, GEN7_FF_VS_REF_CNT_FFME);
}
+static void
+gen9_wa_init_mcr(struct drm_i915_private *i915, struct i915_wa_list *wal)
+{
+ const struct sseu_dev_info *sseu = &i915->gt.info.sseu;
+ unsigned int slice, subslice;
+ u32 mcr, mcr_mask;
+
+ GEM_BUG_ON(GRAPHICS_VER(i915) != 9);
+
+ /*
+ * WaProgramMgsrForCorrectSliceSpecificMmioReads:gen9,glk,kbl,cml
+ * Before any MMIO read into slice/subslice specific registers, MCR
+ * packet control register needs to be programmed to point to any
+ * enabled s/ss pair. Otherwise, incorrect values will be returned.
+ * This means each subsequent MMIO read will be forwarded to an
+ * specific s/ss combination, but this is OK since these registers
+ * are consistent across s/ss in almost all cases. In the rare
+ * occasions, such as INSTDONE, where this value is dependent
+ * on s/ss combo, the read should be done with read_subslice_reg.
+ */
+ slice = ffs(sseu->slice_mask) - 1;
+ GEM_BUG_ON(slice >= ARRAY_SIZE(sseu->subslice_mask));
+ subslice = ffs(intel_sseu_get_subslices(sseu, slice));
+ GEM_BUG_ON(!subslice);
+ subslice--;
+
+ /*
+ * We use GEN8_MCR..() macros to calculate the |mcr| value for
+ * Gen9 to address WaProgramMgsrForCorrectSliceSpecificMmioReads
+ */
+ mcr = GEN8_MCR_SLICE(slice) | GEN8_MCR_SUBSLICE(subslice);
+ mcr_mask = GEN8_MCR_SLICE_MASK | GEN8_MCR_SUBSLICE_MASK;
+
+ drm_dbg(&i915->drm, "MCR slice:%d/subslice:%d = %x\n", slice, subslice, mcr);
+
+ wa_write_clr_set(wal, GEN8_MCR_SELECTOR, mcr_mask, mcr);
+}
+
static void
gen9_gt_workarounds_init(struct intel_gt *gt, struct i915_wa_list *wal)
{
struct drm_i915_private *i915 = gt->i915;
+ /* WaProgramMgsrForCorrectSliceSpecificMmioReads:glk,kbl,cml,gen9 */
+ gen9_wa_init_mcr(i915, wal);
+
/* WaDisableKillLogic:bxt,skl,kbl */
if (!IS_COFFEELAKE(i915) && !IS_COMETLAKE(i915))
wa_write_or(wal,
--
2.38.1