On Wed, Jul 30, 2014 at 3:10 PM, Thierry Reding <thierry.reding@xxxxxxxxx> wrote: > On Wed, Jul 30, 2014 at 11:54:00AM +0530, Ajay kumar wrote: >> Hi Thierry, >> >> On Tue, Jul 29, 2014 at 5:17 PM, Thierry Reding >> <thierry.reding@xxxxxxxxx> wrote: >> > On Tue, Jul 29, 2014 at 01:42:09PM +0200, Andreas Färber wrote: >> >> Am 29.07.2014 13:36, schrieb Thierry Reding: >> >> > On Tue, Jul 29, 2014 at 01:21:48PM +0200, Andreas Färber wrote: >> >> >> Hi Ajay, >> >> >> >> >> >> Am 28.07.2014 08:13, schrieb Ajay kumar: >> >> >>> On 7/27/14, Andreas Färber <afaerber@xxxxxxx> wrote: >> >> >>>> Am 25.07.2014 21:22, schrieb Ajay Kumar: >> >> >>>>> This series is based on exynos-drm-next branch of Inki Dae's tree at: >> >> >>>>> git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos.git >> >> >>>>> >> >> >>>>> I have tested this after adding few DT changes for exynos5250-snow, >> >> >>>>> exynos5420-peach-pit and exynos5800-peach-pi boards. >> >> >>>> >> >> >>>> I'm trying to test this with a modified exynos5250-spring DT >> >> [...] >> >> >> Unfortunately the most I got on Spring with attached DT was a blank >> >> >> screen with a white horizontal line in the middle. >> >> >> >> >> >> Do I need to specify a specific panel model for Spring? >> >> [...] >> >> >> From 9172a26a8f0d0f0d170bd27e1c150ad204d8086a Mon Sep 17 00:00:00 2001 >> >> >> From: =?UTF-8?q?Andreas=20F=C3=A4rber?= <afaerber@xxxxxxx> >> >> >> Date: Sun, 27 Jul 2014 21:58:06 +0200 >> >> >> Subject: [PATCH] ARM: dts: exynos5250: Add eDP/LVDS bridge to Spring >> >> >> MIME-Version: 1.0 >> >> >> Content-Type: text/plain; charset=UTF-8 >> >> >> Content-Transfer-Encoding: 8bit >> >> >> >> >> >> Signed-off-by: Ajay Kumar <ajaykumar.rs@xxxxxxxxxxx> >> >> >> [AF: Redone for v6] >> >> >> Signed-off-by: Andreas F??rber <afaerber@xxxxxxx> >> >> >> --- >> >> >> arch/arm/boot/dts/exynos5250-spring.dts | 32 +++++++++++++++++++++++++++++++- >> >> >> 1 file changed, 31 insertions(+), 1 deletion(-) >> >> >> >> >> >> diff --git a/arch/arm/boot/dts/exynos5250-spring.dts b/arch/arm/boot/dts/exynos5250-spring.dts >> >> >> index 687dfab86bc8..517b1ff2bfdf 100644 >> >> >> --- a/arch/arm/boot/dts/exynos5250-spring.dts >> >> >> +++ b/arch/arm/boot/dts/exynos5250-spring.dts >> >> >> @@ -64,10 +64,14 @@ >> >> >> vdd_pll-supply = <&s5m_ldo8_reg>; >> >> >> }; >> >> >> >> >> >> + panel: panel { >> >> >> + compatible = "simple-panel"; >> >> >> + }; >> >> > >> >> > You can't do this. "simple-panel" isn't a valid panel model. It should >> >> > probably be removed from the platform_of_match table in the driver. >> >> >> >> Okay, that means the Snow DT is wrong, too: >> >> https://patchwork.kernel.org/patch/4625441/ >> >> >> >> And the others specify it as fallback: >> >> https://patchwork.kernel.org/patch/4625461/ >> >> https://patchwork.kernel.org/patch/4625451/ >> > >> > A quick grep shows that many (all?) devices that use DRM panels provide >> > simple-panel as fallback. That's probably fine as long as they also do >> > provide the specific model. But given that simple-panel does not have a >> > mode or physical size, I don't think even that makes sense. >> On snow, the bridge chip provides the display mode instead of the panel. >> That is why display was working for me. > > Okay, I suppose under some circumstances that might make sense. Although > it's still always the panel that dictates the display timings, so the > panel node needs to have a panel model specific compatible value with a > matching entry in the panel-simple driver so that it can even be used in > setups without a bridge. Well, I am okay with adding the compatible value for specific panel model because "simple-panel" alone cannot provide width/height of the panel. > One other thing: how does the bridge know which mode to drive? I suspect > that it can drive more than one mode? Can it freely be configured or > does it have a predefined set of modes? If the latter, then according to > what you said above there needs to be a way to configure the bridge (via > DT?) so that it reports the mode matching the panel. I wonder if that > should be handled completely in code, so that for example a bridge has a > panel attached it can use the panel's .get_modes() and select a matching > mode among the set that it supports. ptn3460 supports a standard list of "edid-emulation" ids. As of now, we receive that as a DT entry. And, these are the list of emulation ids supported: | Value | Resolution | Description | 0 | 1024x768 | NXP Generic | 1 | 1920x1080 | NXP Generic | 2 | 1920x1080 | NXP Generic | 3 | 1600x900 | Samsung LTM200KT | 4 | 1920x1080 | Samsung LTM230HT | 5 | 1366x768 | NXP Generic | 6 | 1600x900 | ChiMei M215HGE As you can see, the same resolutions have different emulator ids. May be, it depends on panel vendor also. I am really not sure if we can do this. For snow(which has 1366x768 panel), we set edid-emulation as 5. Ajay -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html