<div dir="ltr"><div>Hi Steffen Trumtrar and Sascha Hauer,<br><br></div>Olof and Tomasz Figa have a concern in putting "display-timings" as root node in device tree file.<br><div class="gmail_extra"><br><br><div class="gmail_quote">
On 10 May 2013 13:45, Vikas Sajjan <span dir="ltr"><<a href="mailto:vikas.sajjan@linaro.org" target="_blank">vikas.sajjan@linaro.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">HI Tomasz,<br><div class="gmail_extra"><br><br><div class="gmail_quote"><div><div class="h5">On 10 May 2013 13:03, Tomasz Figa <span dir="ltr"><<a href="mailto:tomasz.figa@gmail.com" target="_blank">tomasz.figa@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div>On Friday 10 of May 2013 11:57:34 Vikas Sajjan wrote:<br>
> Hi Olof,<br>
><br>
> On 10 May 2013 11:51, Vikas Sajjan <<a href="mailto:vikas.sajjan@linaro.org" target="_blank">vikas.sajjan@linaro.org</a>> wrote:<br>
> > Hi Olof,<br>
> ><br>
> > On 10 May 2013 11:08, Olof Johansson <<a href="mailto:olof@lixom.net" target="_blank">olof@lixom.net</a>> wrote:<br>
> >> On Thu, May 9, 2013 at 7:55 PM, Vikas Sajjan<br>
> >> <<a href="mailto:vikas.sajjan@linaro.org" target="_blank">vikas.sajjan@linaro.org</a>><br>
> >><br>
> >> wrote:<br>
> >> > Hi Tomasz,<br>
> >> ><br>
> >> > On 10 May 2013 05:35, Tomasz Figa <<a href="mailto:tomasz.figa@gmail.com" target="_blank">tomasz.figa@gmail.com</a>> wrote:<br>
> >> >> Hi Vikas,<br>
> >> >><br>
> >> >> On Wednesday 08 of May 2013 11:31:34 Vikas Sajjan wrote:<br>
> >> >> > Adds display timing node for a DP panel to Arndale Board DTS<br>
> >> >> > file<br>
> >> >> ><br>
> >> >> > Signed-off-by: Vikas Sajjan <<a href="mailto:vikas.sajjan@linaro.org" target="_blank">vikas.sajjan@linaro.org</a>><br>
> >> >> > ---<br>
> >> >> ><br>
> >> >> > arch/arm/boot/dts/exynos5250-arndale.dts | 16<br>
> >> >> > ++++++++++++++++<br>
> >> >> > 1 file changed, 16 insertions(+)<br>
> >> >> ><br>
> >> >> > diff --git a/arch/arm/boot/dts/exynos5250-arndale.dts<br>
> >> >> > b/arch/arm/boot/dts/exynos5250-arndale.dts index<br>
> >> >> > f68b820..c831a5c<br>
> >> >> > 100644<br>
> >> >> > --- a/arch/arm/boot/dts/exynos5250-arndale.dts<br>
> >> >> > +++ b/arch/arm/boot/dts/exynos5250-arndale.dts<br>
> >> >> > @@ -459,4 +459,20 @@<br>
> >> >> ><br>
> >> >> > samsung,lane-count = <4>;<br>
> >> >> ><br>
> >> >> > };<br>
> >> >> ><br>
> >> >> > + display-timings {<br>
> >> >> > + native-mode = <&timing0>;<br>
> >> >> > + timing0: timing@0 {<br>
> >> >> > + /* 2560x1600 DP panel */<br>
> >> >> > + clock-frequency = <50000>;<br>
> >> >> > + hactive = <2560>;<br>
> >> >> > + vactive = <1600>;<br>
> >> >> > + hfront-porch = <48>;<br>
> >> >> > + hback-porch = <80>;<br>
> >> >> > + hsync-len = <32>;<br>
> >> >> > + vback-porch = <16>;<br>
> >> >> > + vfront-porch = <8>;<br>
> >> >> > + vsync-len = <6>;<br>
> >> >> > + };<br>
> >> >> > + };<br>
> >> >><br>
> >> >> What display are those timings used for? Shouldn't they be placed<br>
> >><br>
> >> inside<br>
> >><br>
> >> >> node of that display?<br>
> >> ><br>
> >> > This timing information will be used parsed by the FIMD probe with<br>
> >> > the<br>
> >><br>
> >> help<br>
> >><br>
> >> > of "Video Helper function" as done in this link<br>
> >><br>
> >> <a href="https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/c" target="_blank">https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/c</a><br>
> >> ommit/?h=exynos-drm-next&id=7f4596f4aebcc9fcf2d50d3fe398508d710c4dd0<br>
> >><br>
> >> That function passes in a device node pointer to the FIMD device<br>
> >> node,<br>
> >> and only looks for a display-timings node under there. Tomasz is<br>
> >> right, as far as I can tell.<br>
> >><br>
> >> Placing display timings at the root of the device tree seems<br>
> >> completely<br>
> >> wrong.<br>
> >><br>
> >> I referred this "<br>
><br>
> Documentation/devicetree/bindings/video/display-timing.txt" for example<br>
><br>
> here it dosen't mention about whether display timings node<br>
> can be placed at the root of the device tree or NOT.<br>
> Not sure how we should be placing the node then.<br>
<br>
</div></div>I think this is pretty obvious.<br>
<br>
Imagine a bit more complex case: a board has two video outputs (let's say<br>
FIMD0 and FIMD1), each connected to a completely different display. This<br>
means that each display needs different timings.<br>
<br>
How would you know which timings to use if all of them were be placed<br>
under the root node?<br>
<br></blockquote></div></div><div> so what do you think, how should we modify this patch so that it belongs to a specific video outputs.<br><br></div></div></div></div></blockquote><div><br></div><div><br> So what do you think, how should we modify this patch so that it belongs to a specific video outputs. <br>
</div><div><br><br> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div></div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Best regards,<br>
Tomasz<br>
<br>
</blockquote></div><div class="im"><br><br clear="all"><br>-- <br>Thanks and Regards<div> Vikas Sajjan</div>
</div></div></div>
</blockquote></div><br><br clear="all"><br>-- <br>Thanks and Regards<div> Vikas Sajjan</div>
</div></div>