Re: [PATCH] drm/msm/mdp5: enable clocks in hw_init and set_irqmask

[hali@codeaurora.org]

> 2015-08-26 9:55 GMT-04:00  <hali@codeaurora.org>:
>> Hi Archit,
>>
>>> mdp5_hw_init and mdp5_set_irqmask configure registers but may not have
>>> clocks enabled.
>>>
>>> Add mdp5_enable/disable calls in these funcs to ensure clocks are
>>> enabled. We need this until we get proper runtime pm support.
>>>
>>> Signed-off-by: Archit Taneja <architt@codeaurora.org>
>>> ---
>>>  drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c | 10 ++++++++--
>>>  drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c |  2 ++
>>>  2 files changed, 10 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c
>>> b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c
>>> index b1f73be..9fabfca 100644
>>> --- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c
>>> +++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c
>>> @@ -24,9 +24,15 @@
>>>  void mdp5_set_irqmask(struct mdp_kms *mdp_kms, uint32_t irqmask,
>>>               uint32_t old_irqmask)
>>>  {
>>> -     mdp5_write(to_mdp5_kms(mdp_kms), REG_MDP5_MDP_INTR_CLEAR(0),
>>> +     struct mdp5_kms *mdp5_kms = to_mdp5_kms(mdp_kms);
>>> +
>>> +     mdp5_enable(mdp5_kms);
>>> +
>>> +     mdp5_write(mdp5_kms, REG_MDP5_MDP_INTR_CLEAR(0),
>>>               irqmask ^ (irqmask & old_irqmask));
>>> -     mdp5_write(to_mdp5_kms(mdp_kms), REG_MDP5_MDP_INTR_EN(0),
>>> irqmask);
>>> +     mdp5_write(mdp5_kms, REG_MDP5_MDP_INTR_EN(0), irqmask);
>>> +
>>> +     mdp5_disable(mdp5_kms);
>>>  }
>>
>> mdp5_set_irqmask() can be invoked in atomic context, clk_prepare() is
>> not
>> allowed in this function because it may cause process to sleep. We can
>> enable the clocks in the caller at initialization.
>
> iirc, it will be called with at least one spinlock held..
>
> We do already move the enable/disable_vblank() paths off to a worker
> so that we can ensure things are enabled before we get into
> update_irq()..  the only other path to update_irq() should be when
> driver code does mdp_irq_register/unregister().. so maybe we should
> just require that the mdp4/mdp5 kms code only calls those when clk's
> are already enabled (which should be mostly true already, I think)
>
> BR,
> -R

Yes, the only case that not been covered is mdp5_irq_postinstall(). We can
enable clocks in this function. Actually, this is what we are doing in
downstream test.
>
>>>
>>>  static void mdp5_irq_error_handler(struct mdp_irq *irq, uint32_t
>>> irqstatus)
>>> diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
>>> b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
>>> index 047cb04..2b760f5 100644
>>> --- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
>>> +++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
>>> @@ -32,6 +32,7 @@ static int mdp5_hw_init(struct msm_kms *kms)
>>>       unsigned long flags;
>>>
>>>       pm_runtime_get_sync(dev->dev);
>>> +     mdp5_enable(mdp5_kms);
>>>
>>>       /* Magic unknown register writes:
>>>        *
>>> @@ -63,6 +64,7 @@ static int mdp5_hw_init(struct msm_kms *kms)
>>>
>>>       mdp5_ctlm_hw_reset(mdp5_kms->ctlm);
>>>
>>> +     mdp5_disable(mdp5_kms);
>>>       pm_runtime_put_sync(dev->dev);
>>>
>>>       return 0;
>>> --
>>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>>> Forum,
>>> hosted by The Linux Foundation
>>>
>>>
>>
>>
>


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