lkml.org 
[lkml]   [2018]   [Nov]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v2 01/12] drm/sun4i: sun6i_mipi_dsi: Compute burst mode loop N1 instruction delay
On Tue, Nov 20, 2018 at 9:29 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
>
> On Tue, Nov 20, 2018 at 07:06:30PM +0530, Jagan Teki wrote:
> > On Tue, Nov 20, 2018 at 6:53 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > >
> > > On Mon, Nov 19, 2018 at 04:28:29PM +0530, Jagan Teki wrote:
> > > > On Mon, Nov 19, 2018 at 1:57 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > > > >
> > > > > On Fri, Nov 16, 2018 at 10:09:05PM +0530, Jagan Teki wrote:
> > > > > > Loop N1 instruction delay for burst mode lcd panel are
> > > > > > computed as per BSP code.
> > > > > >
> > > > > > Reference code is available in BSP (from linux-sunxi
> > > > > > drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c)
> > > > > >
> > > > > > dsi_dev[sel]->dsi_inst_loop_num.bits.loop_n1=
> > > > > > (panel->lcd_ht-panel->lcd_x)*(150)/(panel->lcd_dclk_freq*8) - 50;
> > > > > > => (((mode->htotal - mode->hdisplay) * 150) /
> > > > > > ((mode->clock / 1000) * 8)) - 50;
> > > > > >
> > > > > > So use the similar computation for loop N1 delay.
> > > > > >
> > > > > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> > > > >
> > > > > *why* are you doing this? What is it fixing? on which devices?
> > > >
> > > > You mentioned the separate function to compute the delay for all modes
> > > > [1], ie what I did. did I missing anything?
> > >
> > > You're missing that you are never explaining why that patch is needed
> > > in the first place. Or answering the question I asked a couple of
> > > lines above.
> >
> > OK.
> >
> > The instruction delay varies between video and burst mode. for burst
> > mode panels it is computed based on the panel clock along with
> > horizontal sync+porch timings.
>
> You're still stating a fact. What issue, that you experienced, are you
> trying to solve here?

This change is specific for burst mode instruction delay. for
non-burst it is 50 - 1 and for burst mode it is computed as mentioned
in commit message. Both things are available in BSP code. and without
this burst mode panels not working with existing (50 - 1)

\
 
 \ /
  Last update: 2018-11-20 17:21    [W:0.063 / U:0.864 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site