[Intel-gfx] [PATCH] drm/i915: There is only one fault register from Gen8 onwards

[Michel Thierry]

On 23/06/17 16:35, Chris Wilson wrote:
> Quoting Michel Thierry (2017-06-24 00:17:29)
>> Until Haswell/Baytrail, the hardware used to have a per engine fault
>> register (e.g. 0x4094 - render fault register, 0x4194 - media fault
>> register, etc). But since Broadwell, all these registers were combined
>> into a singe one, which specifies the engine id in bits 14:12.
>>
>> Luckily, the additional register addresses haven't been reused, but we
>> should not been reading (and writing to) registers that do not exist.
>>
>> References: IHD-OS-BDW-Vol 2c-11.15, page 75.
>> Signed-off-by: Michel Thierry <michel.thierry at intel.com>
>> ---
>>  drivers/gpu/drm/i915/i915_gem_gtt.c   | 29 ++++++++++++++++++++++++-----
>>  drivers/gpu/drm/i915/i915_gpu_error.c |  8 +++++---
>>  drivers/gpu/drm/i915/i915_reg.h       |  2 ++
>>  3 files changed, 31 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
>> index de67084d5fcf..83deb004368c 100644
>> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
>> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
>> @@ -2000,22 +2000,41 @@ void i915_check_and_clear_faults(struct drm_i915_private *dev_priv)
>>         if (INTEL_INFO(dev_priv)->gen < 6)
>>                 return;
>>
>> -       for_each_engine(engine, dev_priv, id) {
>> +       /* From GEN8 onwards we only have one 'All Engine Fault Register' */
>> +       if (INTEL_INFO(dev_priv)->gen >= 8) {
> INTEL_GEN() >= 8
>

Oops, busted copy-pasting old code, I'll also change it 
(INTEL_INFO(dev_priv)->gen < 6).

>>                 u32 fault_reg;
>
> Newline after variable blocks (might as well fix up the coding style in
> passing).
>
> u32 fault;
>
> foo_reg is more commonly used to refer to the register offset itself,
> i.e. i915_reg_t.  Might as well move it to the start of the function as
> it is shared between all branches, and I don't think we are overly
> concerned with aiding gcc's liverange analysis here.

I thought about moving it to the start of the function. Let me make 
these changes.

Thanks,

-Michel