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

[Hoegeun Kwon]

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

goes from off to on. The cause of this problem is that when we put pm idle,

I think that there is a timing problem if I do not sync.


Best regards,

Hoegeun


>
>> Signed-off-by: Hoegeun Kwon <hoegeun.kwon at samsung.com>
>> ---
>>   drivers/gpu/drm/vc4/vc4_dsi.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
>> index 11702e1d9011..b0264c7b8bed 100644
>> --- a/drivers/gpu/drm/vc4/vc4_dsi.c
>> +++ b/drivers/gpu/drm/vc4/vc4_dsi.c
>> @@ -822,7 +822,7 @@ static void vc4_dsi_encoder_disable(struct drm_encoder *encoder)
>>   	clk_disable_unprepare(dsi->escape_clock);
>>   	clk_disable_unprepare(dsi->pixel_clock);
>>   
>> -	pm_runtime_put(dev);
>> +	pm_runtime_put_sync(dev);
>>   }
>>   
>>   /* Extends the mode's blank intervals to handle BCM2835's integer-only
>> -- 
>> 2.17.1