[Intel-gfx] [PATCH 4/4] drm/i915: Extend WaDisableIPC to all platforms.

[Mahesh Kumar]

Hi,

sorry for late reply, it was India site holiday.

On Friday 29 September 2017 12:42 AM, Rodrigo Vivi wrote:
> On Thu, Sep 28, 2017 at 07:02:59PM +0000, Chris Wilson wrote:
>> Quoting Rodrigo Vivi (2017-09-28 19:51:48)
>>> Although Bspec state this Workaround is only relevant for SKL:All.
>>>
>>> The wa_database state this is needed for All platforms from SKL to CNL.
>>>
>>> So let's pick the safest case.
>>>
>>> Cc: Mahesh Kumar <mahesh1.kumar at intel.com>
>>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>>> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>>> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/intel_pm.c | 4 ++--
>>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>>> index ede871b7982e..27f9d5ab2d23 100644
>>> --- a/drivers/gpu/drm/i915/intel_pm.c
>>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>>> @@ -5828,8 +5828,8 @@ void intel_enable_ipc(struct drm_i915_private *dev_priv)
>>>   {
>>>          u32 val;
>>>   
>>> -       /* Display WA #0477 WaDisableIPC: skl */
>>> -       if (IS_SKYLAKE(dev_priv)) {
>>> +       /* Display WA #0477 WaDisableIPC: skl,kbl,bxt,glk,cfl,cnl */
>>> +       if (INTEL_GEN(dev_priv) <= 10) {
WA #0477 asks us to disable IPC for SKL:ALL, for all other GEN9 variant 
it should be enabled.
Enabling IPC improves performance of other memory clients, as without 
IPC enabled display always fetches from memory with High-priority.

-Mahesh
>> But at that point, why not just define has_ipc as a gen10 feature?
> it's already there...
>
>> You
>> can have a comment before gen9 feature that although IPC was introduced
>> for gen9, it is recommended (w/a) to leave disabled.
> so you mean moving this Wa from here to set has_ipc = 0 to all platforms?
>
> Anyways I'd like to hear from Manesh about it since this basically revert
> all IPC work for all platforms...
>
>> -Chris