Re: [PATCH] drm: rcar-du: Re-update the DSYSR register value for start/stop

[Hoan <na-hoan@jinso.co.jp>]

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Dear Laurent-san

On 2018/10/22 20:23, Laurent Pinchart wrote:
> Hello Hoan,
>
> Thank you for the patch.
>
> On Monday, 22 October 2018 09:30:54 EEST Nguyen An Hoan wrote:
>> From: Hoan Nguyen An <na-hoan@jinso.co.jp>
>>
>>  From previous commit 0521ccb "drm: rcar-du: Cache DSYSR value to ensure
>> known initial value"
> What exact commit are you referring to ? The mainline commit that has this
> subject is 9144adc5e5a99577bce0d4ee2ca3615f53b9d296.
>
>> We only need to update DSYSR0, DSYSR2 for start/stop.
>> So using rgrp-> mmio_offset is enough, the change back from rcar_du_crtc ->
>> rcar_du_group -> rcar_du_crtc leading to mmio addresses for DSYSR may be
>> different.
> Is this fixing an actual problem ? If you look at the code, the line
>
> 	struct rcar_du_crtc *rcrtc = &rgrp->dev->crtcs[rgrp->index * 2];
>
> makes sure that we select DU0 or DU2 only, so the register write
>
> 	rcar_du_crtc_dsysr_clr_set(rcrtc, DSYSR_DRES | DSYSR_DEN,
> 				   start ? DSYSR_DEN : DSYSR_DRES);
>
> should only access DSYSR0 and DSYSR2.

Dear Laurent-san

I add information about the current error occurring at M3N-r8a77965

when probe rcar-du driver:

/[   13.027115] [drm:drm_atomic_helper_wait_for_flip_done] *ERROR* 
[CRTC:55:crtc-2] flip_done timed out//
//[   23.267103] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* 
[CRTC:55:crtc-2] flip_done timed out//
//[   33.507102] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* 
[CONNECTOR:57:VGA-1] flip_done timed out//
//[   43.747100] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* 
[PLANE:30:plane-1] flip_done timed out//
//[   53.987100] [drm:drm_atomic_helper_wait_for_flip_done] *ERROR* 
[CRTC:55:crtc-2] flip_done timed out//
//[   53.989913] Console: switching to colour frame buffer device 128x48//
//[   64.227102] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* 
[CRTC:55:crtc-2] flip_done timed out//
//[   74.467099] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* 
[CONNECTOR:57:VGA-1] flip_done timed out//
//[   84.707100] [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* 
[PLANE:30:plane-1] flip_done timed out//
//[   94.947100] [drm:drm_atomic_helper_wait_for_flip_done] *ERROR* 
[CRTC:55:crtc-2] flip_done timed out//
//[   95.040076] rcar-du feb00000.display: fb0: DRM emulated frame 
buffer device//
//[   95.047747] [drm] Initialized rcar-du 1.0.0 20130110 for 
feb00000.display on minor 0//
//[   95.055512] [drm] Device feb00000.display probed//
//[   95.061252] bd9571mwv 7-0030: Device: BD9571MWV rev. 4/

on renesas-drivers/renesas-drivers-2018-10-09-v4.19-rc7

Thank you!

Hoan.


>> Signed-off-by: Hoan Nguyen An <na-hoan@jinso.co.jp>
>> ---
>>   drivers/gpu/drm/rcar-du/rcar_du_group.c | 7 +++----
>>   1 file changed, 3 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.c
>> b/drivers/gpu/drm/rcar-du/rcar_du_group.c index d85f0a1..a5f7eed 100644
>> --- a/drivers/gpu/drm/rcar-du/rcar_du_group.c
>> +++ b/drivers/gpu/drm/rcar-du/rcar_du_group.c
>> @@ -202,10 +202,9 @@ void rcar_du_group_put(struct rcar_du_group *rgrp)
>>
>>   static void __rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool
>> start) {
>> -	struct rcar_du_crtc *rcrtc = &rgrp->dev->crtcs[rgrp->index * 2];
>> -
>> -	rcar_du_crtc_dsysr_clr_set(rcrtc, DSYSR_DRES | DSYSR_DEN,
>> -				   start ? DSYSR_DEN : DSYSR_DRES);
>> +	rcar_du_group_write(rgrp, DSYSR,
>> +			(rcar_du_group_read(rgrp, DSYSR) & ~(DSYSR_DRES | DSYSR_DEN)) |
>> +			(start ? DSYSR_DEN : DSYSR_DRES));
>>   }
>>
>>   void rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start)

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