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.

Signed-off-by: Kenneth Graunke kenneth@whitecape.org Cc: stable@vger.kernel.org --- drivers/gpu/drm/i915/i915_reg.h | 2 ++ drivers/gpu/drm/i915/intel_engine_cs.c | 5 +++++ 2 files changed, 7 insertions(+)

Hello,

We unfortunately need to whitelist an extra register for GPU hang fix on Geminilake. Here's the corresponding Mesa patch:

https://patchwork.freedesktop.org/patch/196047/

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 966e4df9700e..505c605eff98 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -7079,6 +7079,8 @@ enum { #define GEN9_SLICE_COMMON_ECO_CHICKEN0 _MMIO(0x7308) #define DISABLE_PIXEL_MASK_CAMMING (1<<14)

+#define GEN9_SLICE_COMMON_ECO_CHICKEN1 _MMIO(0x731c) + #define GEN7_L3SQCREG1 _MMIO(0xB010) #define VLV_B0_WA_L3SQCREG1_VALUE 0x00D30000

diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index ebdcbcbacb3c..d64a9f907550 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -1338,6 +1338,11 @@ static int glk_init_workarounds(struct intel_engine_cs *engine) if (ret) return ret;

+ /* Userspace needs to toggle "Barrier Mode" to avoid GPU 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);