Re: [PATCH 2/2] drm/panel: boe-tv101wum-nl6: Reduce lcm_reset to send initial code time

["Xinlei Lee (李昕磊)" <Xinlei.Lee@mediatek.com>]

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On Mon, 2023-01-09 at 12:25 +0100, AngeloGioacchino Del Regno wrote:
> Il 06/01/23 04:05, xinlei.lee@mediatek.com ha scritto:
> > From: Xinlei Lee <xinlei.lee@mediatek.com>
> > 
> > Since the panel spec stipulates that the time from lcm_reset to DSI
> > to
> > send the initial code should be greater than 6ms and less than
> > 40ms,
> > so reduce the delay before sending the initial code and avoid panel
> > exceptions.
> > 
> > Fixes: a869b9db7adf ("drm/panel: support for boe tv101wum-nl6 wuxga
> > dsi video mode panel")
> > Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> > ---
> >   drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c | 1 -
> >   1 file changed, 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
> > b/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
> > index 857a2f0420d7..f0093035f1ff 100644
> > --- a/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
> > +++ b/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
> > @@ -780,7 +780,6 @@ static const struct panel_init_cmd
> > inx_hj110iz_init_cmd[] = {
> >   };
> >   
> >   static const struct panel_init_cmd boe_init_cmd[] = {
> > -	_INIT_DELAY_CMD(24),
> 
> You said that should be greater than 6 and less than 40: perhaps on
> MediaTek
> platforms removing this delay is fine but we don't know about others
> - and this
> driver is for all platforms.
> 
> To stay on the safe side you should, at this point, replace this
> delay with
> 
> 	_INIT_DELAY_CMD(7);
> 
> Regards,
> Angelo
> 

Hi Angelo:

Thanks for your reply!

Please allow me to explain, in another dsi modification of this 
series, I reduced the delay of dsi's LP00->LP11 stage from 20ms to 1ms 
(to comply with dsi spec), in fact, in this file, the
boe_panel_prepare function The 6ms delay after pulling up lcm_reset
is before the 1ms mentioned just now, which ensures that the delay is 
within the specified range (7ms).

Do you still have doubts about my explanation?

Best Regards!
xinlei