On Sun, 22 Jan 2023, "Usyskin, Alexander" <alexander.usyskin@xxxxxxxxx> wrote:
>> > diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
>> b/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
>> > index d50354bfb993..bef6d7f8ac55 100644
>> > --- a/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
>> > +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
>> > @@ -127,6 +127,10 @@ static int i915_pxp_tee_component_bind(struct
>> device *i915_kdev,
>> > intel_wakeref_t wakeref;
>> > int ret = 0;
>> >
>> > + if (!HAS_HECI_PXP(i915) &&
>> > + drm_WARN_ON(&i915->drm, !device_link_add(i915_kdev,
>> tee_kdev,
>>
>> I don't like the action here hidden behind the drm_WARN_ON.
>> Please notice that almost every use of this and other helpers like
>> this expect the param as a failure. Not an actual action. So,
>> most of lazy readers like me might ignore that the main function
>> is actually a param inside this warn condition.
>>
> Honestly, copy-pasted from drivers/gpu/drm/i915/display/intel_audio.c +1266
> I don't have deep knowledge of drm macros, so thought this should be ok.
> Can make it any other form that acceptable in drm tree...
Unfortunately, some pattern being present in the driver does not mean
it's a good example to be emulated. If we copy a bad pattern, it seems
more acceptable, and even more people will copy it.
BR,
Jani.
>
>> We should probably stash the link as well...
>>
>> pxp->dev_link = device_link_add(i915_kdev, tee_kdev,...);
>>
>> so in the end below, instead of checking the HAS_HECI_PXP again
>> and use the remove version you check the dev_link and use the del
>> function.
>>
>> something like:
>>
>> if (pxp->dev_link)
>> device_link_del(pxp->dev_link);
>>
> Not sure that this simplification warrants additional clutter in struct.
>
>> Also, do you really need the WARN to see the stack when this happens
>> or you already know the callers?
>> Why not a simple drm_error msg?
>>
>> if (!HAS_HECI_PXP(i915) {
>> pxp->dev_link = device_link_add(i915_kdev, tee_kdev,...);
>> if (!pxp->dev_link) {
>> drm_error();
>> return -ESOMETHING;
>>
>> > DL_FLAG_STATELESS)))
>>
>> do we need the RPM in sync as well?
>> I mean:
>>
>> DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME)))
>>
>> ?
>
> No, the mei device should not be active all the time when i915 is active, only when pxp requires it.
>
>>
>> > + return -ENOMEM;
>>
>> why ENOMEM?
> Copy-paste from i915 audio.
>
>>
>> > +
>> > mutex_lock(&pxp->tee_mutex);
>> > pxp->pxp_component = data;
>> > pxp->pxp_component->tee_dev = tee_kdev;
>> > @@ -169,6 +173,9 @@ static void i915_pxp_tee_component_unbind(struct
>> device *i915_kdev,
>> > mutex_lock(&pxp->tee_mutex);
>> > pxp->pxp_component = NULL;
>> > mutex_unlock(&pxp->tee_mutex);
>> > +
>> > + if (!HAS_HECI_PXP(i915))
>> > + device_link_remove(i915_kdev, tee_kdev);
>> > }
>> >
>> > static const struct component_ops i915_pxp_tee_component_ops = {
>> > --
>> > 2.39.0
>> >
--
Jani Nikula, Intel Open Source Graphics Center
