On Thu, Apr 30, 2020 at 03:54:38PM +0200, Daniel Vetter wrote:
> On Thu, Apr 30, 2020 at 09:47:46PM +0800, Xin Ji wrote:
> > Hi Daniel,
> >
> > On Thu, Apr 30, 2020 at 03:38:39PM +0200, Daniel Vetter wrote:
> > > On Thu, Apr 30, 2020 at 03:37:31PM +0200, Daniel Vetter wrote:
> > > > On Thu, Apr 30, 2020 at 11:36:14AM +0800, Xin Ji wrote:
> > > > > On Tue, Apr 28, 2020 at 12:05:08PM +0200, Daniel Vetter wrote:
> > > > > > On Fri, Apr 24, 2020 at 08:12:04PM +0800, Nicolas Boichat wrote:
> > > > > > > On Fri, Apr 24, 2020 at 2:51 PM Xin Ji <x...@analogixsemi.com>
> > > > > > > wrote:
> > > > > > > >
> > > > > > > > On Thu, Apr 23, 2020 at 07:55:15PM +0800, Nicolas Boichat wrote:
> > > > > > > > > Hi,
> > > > > > > > >
> > > > > > > > > Just commenting on the mode_fixup function that was added in
> > > > > > > > > v7.
> > > > > > > > >
> > > > > > > > [snip]
> > > > > > > > > > + /*
> > > > > > > > > > + * once illegal timing detected, use default HFP,
> > > > > > > > > > HSYNC, HBP
> > > > > > > > > > + */
> > > > > > > > > > + if (hblanking < HBLANKING_MIN || (hfp < HP_MIN &&
> > > > > > > > > > hbp < HP_MIN)) {
> > > > > > > > >
> > > > > > > > > should this be adj_hblanking/adj_hfp/adj_hbp?
> > > > > > > > NO, need check original HFP and HBP, if they are not legal,
> > > > > > > > driver need
> > > > > > > > set default value to adj_hsync, adj_hfp, adj_hbp.
> > > > > > > > >
> > > > > > > > > > + adj_hsync = SYNC_LEN_DEF;
> > > > > > > > > > + adj_hfp = HFP_HBP_DEF;
> > > > > > > > > > + adj_hbp = HFP_HBP_DEF;
> > > > > > > > > > + vref = adj->clock * 1000 / (adj->htotal *
> > > > > > > > > > adj->vtotal);
> > > > > > > > > > + if (hblanking < HBLANKING_MIN) {
> > > > > > > > > > + delta_adj = HBLANKING_MIN -
> > > > > > > > > > hblanking;
> > > > > > > > > > + adj_clock = vref * delta_adj *
> > > > > > > > > > adj->vtotal;
> > > > > > > > > > + adj->clock +=
> > > > > > > > > > DIV_ROUND_UP(adj_clock, 1000);
> > > > > > > > > > + } else {
> > > > > > > > > > + delta_adj = hblanking -
> > > > > > > > > > HBLANKING_MIN;
> > > > > > > > > > + adj_clock = vref * delta_adj *
> > > > > > > > > > adj->vtotal;
> > > > > > > > > > + adj->clock -=
> > > > > > > > > > DIV_ROUND_UP(adj_clock, 1000);
> > > > > > > > > > + }
> > > > > > > > > > +
> > > > > > > > > > + DRM_WARN("illegal hblanking timing, use
> > > > > > > > > > default.\n");
> > > > > > > > > > + DRM_WARN("hfp(%d),hbp(%d),hsync(%d).\n",
> > > > > > > > > > hfp, hbp, hsync);
> > > > > > > > >
> > > > > > > > > How likely is it that this mode is going to work? Can you
> > > > > > > > > just return
> > > > > > > > > false here to reject the mode?
> > > > > > > > We want to set the default minimal Hblancking value, then it
> > > > > > > > may display,
> > > > > > > > otherwise. If we just return false, there is no display for
> > > > > > > > sure.
> > > > > > >
> > > > > > > Right, understand your argument. I'm pondering if it's not just
> > > > > > > better
> > > > > > > to reject the mode rather than trying a timing that is definitely
> > > > > > > quite different from what the monitor was asking for. No super
> > > > > > > strong
> > > > > > > opinion, I'll let other people on the list weigh in.
> > > > > >
> > > > > > Yeah mode_fixup is supposed to be used to adjust the mode in
> > > > > > intermediate
> > > > > > stages (e.g. if you go from progressive to interlaced only at the
> > > > > > end of
> > > > > > your pipeline or something like that). It's not meant for adjusting
> > > > > > the
> > > > > > mode yout actually put out through a hdmi or dp connector. For fixed
> > > > > > panels adjusting modes to fit the panel is also fairly common, but
> > > > > > not for
> > > > > > external outputs.
> > > > > >
> > > > > > Since this is a DP bridge I'd say no adjusting, just reject what
> > > > > > doesn't
> > > > > > fit.
> > > > > We have found some panel which HBP less than 8, if we reject to adjust
> > > > > video timing, then there is no display. The customer does not accept
> > > > > it,
> > > > > they push us to fix it, the only resolve way is to adjust timing.
> > > >
> > > > Are we talking about external DP screen here, or some built-in panel?
> > > > For
> > > > the later case we do a lot of mode adjusting in many drivers ...
> > > >
> > > > I haven't checked, by if our connector type is eDP then this should be
> > > > all
> > > > fine.
> > >
> > > Ok I read the patch now, you seem to support both. Would it work if we
> > > make this adjustement conditional on it being an internal panel only? I
> > > think that would be perfect.
> > > -Daniel
> > > --
> > > Daniel Vetter
> > > Software Engineer, Intel Corporation
> > Based on comments of V8, only keeped eDP built-in panel in V9 version,
> > removed external DP screen support.
>
> Ah even better. Then the above adjusting has my:
>
> Acked-by: Daniel Vetter <daniel.vet...@ffwll.ch>
>
> Maybe add a comment to the code summarizing the discussion. Definitely
> needs to be covered in the commit message.
OK, I'll add it in the next serial.
Thanks, Xin
>
> Thanks, Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
