On 11/10/2017 3:50 PM, Chris Wilson wrote:
Quoting Michel Thierry (2017-11-10 23:42:31)
On 11/10/2017 12:51 PM, Chris Wilson wrote:
Quoting Michel Thierry (2017-11-10 19:01:16)
Until Haswell/Baytrail, the hardware used to have a per engine fault
register (e.g. 0x4094 - render fault register, 0x4194 - media fault
register and so on). But since Broadwell, all these registers were
combined into a singe one and the engine id stored in bits 14:12.
Not only we should not been reading (and writing to) registers that do
not exist, in platforms with VCS2 (SKL), the address that would belong
this engine (0x4494, VCS2_HW = 4) is already assigned to other register.
References: IHD-OS-BDW-Vol 2c-11.15, page 75.
References: IHD-OS-SKL-Vol 2c-05.16, page 350.
Signed-off-by: Michel Thierry <michel.thierry@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 38 ++++++++++++++++++++++++++++++-----
drivers/gpu/drm/i915/i915_gpu_error.c | 8 +++++---
drivers/gpu/drm/i915/i915_reg.h | 2 ++
3 files changed, 40 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 1e40eeb31f9d..66a907330ad2 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2256,16 +2256,13 @@ static bool needs_idle_maps(struct drm_i915_private *dev_priv)
return IS_GEN5(dev_priv) && IS_MOBILE(dev_priv) && intel_vtd_active();
}
-void i915_check_and_clear_faults(struct drm_i915_private *dev_priv)
+void __check_and_clear_faults(struct drm_i915_private *dev_priv)
I am amazed that -Wextra doesn't complain. Try with sparse.
Hmm, no they didn't... gen6_check_and_clear_faults and
gen8_check_and_clear_faults are less controversial.
The missing static and lack of extern declaration. I know sparse catches
it, I guess for K&R the order is just right for it not to complain.
There's an old thread where this was raised and how we are not clearing
the faults early enough.
Ah, I found that thread [1], and as you said there, right now the
for_each_engine is a nop (with this patch at least gen8+ would do the
right thing).
Since gen6/gen7 engines are well known and can't change, do we really
need for_each_engine?
For consistency, yeah it would be nice to keep for_each_engine. We should
be ok to do the clear around i915_driver_init_mmio (it's mmio, it has to
be there ;), maybe worth pulling it into intel_engines_init_mmio() or
i915_gem_init_mmio(). I'm learning towards sanitization from within
intel_engines_init_mmio()
Ok, I'll move the check_and_clear_faults from intel_uncore_init to
intel_engines_init_mmio (that's the one checking at driver load time).
Thanks,
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