From 4636bda86aa1f34f45c629477476a0dcfa04e597 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Fri, 5 Jan 2018 00:59:05 -0800 Subject: drm/i915: Whitelist SLICE_COMMON_ECO_CHICKEN1 on Geminilake. Geminilake requires the 3D driver to select whether barriers are intended for compute shaders, or tessellation control shaders, by whacking a "Barrier Mode" bit in SLICE_COMMON_ECO_CHICKEN1 when switching pipelines. Failure to do this properly can result in GPU hangs. Unfortunately, this means it needs to switch mid-batch, so only userspace can properly set it. To facilitate this, the kernel needs to whitelist the register. The workarounds page currently tags this as applying to Broxton only, but that doesn't make sense. The documentation for the register it references says the bit userspace is supposed to toggle only exists on Geminilake. Empirically, the Mesa patch to toggle this bit appears to fix intermittent GPU hangs in tessellation control shader barrier tests on Geminilake; we haven't seen those hangs on Broxton. v2: Mention WA #0862 in the comment (it doesn't have a name). Signed-off-by: Kenneth Graunke Acked-by: Rodrigo Vivi Cc: stable@vger.kernel.org Signed-off-by: Rodrigo Vivi Link: https://patchwork.freedesktop.org/patch/msgid/20180105085905.9298-1-kenneth@whitecape.org (cherry picked from commit ab062639edb0412daf6de540725276b9a5d217f9) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_engine_cs.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/gpu/drm/i915/intel_engine_cs.c') diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index ab5bf4e2e28e..6074e04dc99f 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -1390,6 +1390,11 @@ static int glk_init_workarounds(struct intel_engine_cs *engine) if (ret) return ret; + /* WA #0862: Userspace has to set "Barrier Mode" to avoid hangs. */ + ret = wa_ring_whitelist_reg(engine, GEN9_SLICE_COMMON_ECO_CHICKEN1); + if (ret) + return ret; + /* WaToEnableHwFixForPushConstHWBug:glk */ WA_SET_BIT_MASKED(COMMON_SLICE_CHICKEN2, GEN8_SBE_DISABLE_REPLAY_BUF_OPTIMIZATION); -- cgit v1.2.1