[PATCH] drm/vc4: Fix with pm_runtime synchronization on DSI

[Hoegeun Kwon]

On 4/10/19 1:24 AM, Eric Anholt wrote:
> Hoegeun Kwon <hoegeun.kwon at samsung.com> writes:
>
>> On 4/2/19 2:48 AM, Eric Anholt wrote:
>>> Hoegeun Kwon <hoegeun.kwon at samsung.com> writes:
>>>
>>>> There is a problem when often dpms goes from off to on. pm idle is not
>>>> in sync and the problem occurs. Modify pm_runtime_put from
>>>> asynchronous to synchronous.
>>> Why would we need the power domain to go to off before we try to come
>>> back?  Any idea?  Also, please specify what "the problem" is.
>> Hi Eric,
>>
>>
>> First thank you for your review.
>>
>> There is a problem failed to runtime PM enable on DSI when often dpms
> What do you mean by "failed to runtime PM enable"?  The
> pm_runtime_enable() returned an error?  Have you investigated the source
> that error, if so?

I'm sorry for the late reply.

The pm_runtime_enable() is not returned because return value is void.

The problem is that if the error log is not output
and the DPMS off on is repeated, the screen will stop.

As a result of debugging the problem, I think that synchronization
is a problem caused by dsi pm_suspend and resume.

So when we entered the pm runtime idle state, if used with sync,
the problem does not occur.

Best regards,
Hoegeun


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