[Intel-gfx] [RFC 2/6] drm/i915/dp: Move vswing/pre-emphasis adjustment calculation

[Animesh Manna]

On 10/22/2019 11:10 PM, Manasi Navare wrote:
> On Tue, Oct 22, 2019 at 07:34:13PM +0530, Animesh Manna wrote:
>> On 10/22/2019 4:27 AM, Manasi Navare wrote:
>>> On Thu, Oct 03, 2019 at 08:36:49PM +0530, Animesh Manna wrote:
>>>> vswing/pre-emphasis adjustment calculation is needed in processing
>>>> of auto phy compliance request other than link training, so moved
>>>> the same function in intel_dp.c.
>>>>
>>>> No functional change.
>>> You could just make it a non static function instead of moving to intel_dp.c
>> Initially I did the same ... :)
>> Later I thought intel_dp_link_training.c file is mainly focused only on link
>> training process, start_link_train() and stop_link_train() are only exposed.
>> I thought I may not be allowed to expose intel_get_adjust_train() as it is
>> not exclusive for link training.
>> Please let me know your view.
> Infact now that I look at this, i think the prepare_phy_test function should only
> probably get the drm_get_phy_test_pattern and populate in the intel_dp_compliance
> structure and then adjust train and all that can happen right before pattern update
> which will need to happen in atomic_commit_tail.

Okay, in commit-tail we follow modeset sequence and use encoder specific 
hook to do encoder specific programming.
Can you please share your thought about the right place to do DP phy 
compliance specific programming.

>
> How do you handle the regular link training sequence in the case of PHY test?

In automated phy compliance testing as such there is no requirement to 
do link training in between.
Do you see any need of link training in between compliance testing?

> What happens to the adjust train the the regular link training clock recovery and
> channel eq stages?

I felt adjust train calculation can be exposed from intel_dp.c/.h and same like other helper link training process(clock recovery + channel eq) can use it.

Regards,
Animesh

>
> Manasi
>
>> Regards,
>> Animesh