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