[PATCH 47/47] drm/i915/guc: Unblock GuC submission on Gen11+

[Martin Peres]

On 01/07/2021 11:14, Pekka Paalanen wrote:
> On Wed, 30 Jun 2021 11:58:25 -0700
> John Harrison <john.c.harrison at intel.com> wrote:
> 
>> On 6/30/2021 01:22, Martin Peres wrote:
>>> On 24/06/2021 10:05, Matthew Brost wrote:
>>>> From: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>>>>
>>>> Unblock GuC submission on Gen11+ platforms.
>>>>
>>>> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
>>>> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>>>> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
>>>> ---
>>>>    drivers/gpu/drm/i915/gt/uc/intel_guc.h            |  1 +
>>>>    drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c |  8 ++++++++
>>>>    drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h |  3 +--
>>>>    drivers/gpu/drm/i915/gt/uc/intel_uc.c             | 14 +++++++++-----
>>>>    4 files changed, 19 insertions(+), 7 deletions(-)
>>>>
> 
> ...
> 
>>>> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
>>>> b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
>>>> index 7a69c3c027e9..61be0aa81492 100644
>>>> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
>>>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
>>>> @@ -34,8 +34,15 @@ static void uc_expand_default_options(struct
>>>> intel_uc *uc)
>>>>            return;
>>>>        }
>>>>    -    /* Default: enable HuC authentication only */
>>>> -    i915->params.enable_guc = ENABLE_GUC_LOAD_HUC;
>>>> +    /* Intermediate platforms are HuC authentication only */
>>>> +    if (IS_DG1(i915) || IS_ALDERLAKE_S(i915)) {
>>>> +        drm_dbg(&i915->drm, "Disabling GuC only due to old
>>>> platform\n");
>>>
>>> This comment does not seem accurate, given that DG1 is barely out, and
>>> ADL is not out yet. How about:
>>>
>>> "Disabling GuC on untested platforms"?
>>>   
>> Just because something is not in the shops yet does not mean it is new.
>> Technology is always obsolete by the time it goes on sale.
> 
> That is a very good reason to not use terminology like "new", "old",
> "current", "modern" etc. at all.
> 
> End users like me definitely do not share your interpretation of "old".

Yep, old and new is relative. In the end, what matters is the validation 
effort, which is why I was proposing "untested platforms".

Also, remember that you are not writing these messages for Intel 
engineers, but instead are writing for Linux *users*.

Cheers,
Martin

> 
> 
> Thanks,
> pq
> 
> 
>> And the issue is not a lack of testing, it is a question of whether we
>> are allowed to change the default on something that has already started
>> being used by customers or not (including pre-release beta customers).
>> I.e. it is basically a political decision not an engineering decision.
>