From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Zhang Subject: Re: [PATCH] tegra: ventana: display and backlight DT entries Date: Wed, 14 Nov 2012 10:59:48 +0800 Message-ID: <50A30924.4010305@nvidia.com> References: <1352802204-1740-1-git-send-email-acourbot@nvidia.com> <20121113123410.GA11202@avionic-0098.mockup.avionic-design.de> <50A2797C.9030807@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <50A2797C.9030807-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stephen Warren Cc: Thierry Reding , Alex Courbot , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-tegra@vger.kernel.org On 11/14/2012 12:46 AM, Stephen Warren wrote: > On 11/13/2012 05:34 AM, Thierry Reding wrote: >> On Tue, Nov 13, 2012 at 07:23:24PM +0900, Alexandre Courbot wrote: >>> Enable internal panel: - add EDID file - add power sequence to >>> control backlight and panel (panel is currently controlled by the >>> backlight sequence, this will need to be fixed once the panel >>> framework has power sequences support) >>> >>> Also enable HDMI output. > >>> diff --git a/arch/arm/boot/dts/tegra20-ventana.dts >>> b/arch/arm/boot/dts/tegra20-ventana.dts > >>> + rgb { + status = "okay"; + nvidia,edid = >>> /incbin/("tegra20-ventana.edid"); >> >> We've briefly discussed this on IRC already, but for the sake of >> completeness I'll restate it here. I think this should be converted >> to the bindings as defined by the videomode helpers. These are not >> merged yet, but they provide a much more readable representation >> than a binary blob. >> >> I know that Stephen mentioned using the nvidia,edid property for >> boards where the blob is actually available in some sort. I seem to >> remember him mentioning Ventana in particular, but I may be wrong. > > I do tend to think that we should use EDID where there is one. > > 1) If there is an EDID in the panel HW, and the panel's I2C is hooked > up to Tegra, we should read it out at runtime. > > 2) Otherwise, if the panel's documentation provides an EDID, we should > use that, since it's the most canonical/common/standard representation > of the panel's properties. > > 3) Otherwise, use the videomode DT bindings. > > Another benefit of (2) is that we can actually support the panel > without waiting for the videomode DT bindings to be finalized and merged. > Basically I agree with you. Although EDID blob is not friendly to read but it's more flexible. In addition, I recall I can use "i2cget" to get the EDID of Ventana's panel but I've no idea why we can't do that in drm driver. I can spend some time to take a look at this again and if the EDID can be fetched dynamically, I think it's no need to consider videomode DT bindings anymore. > Although if Ventana requires the power sequences helpers, that already > means we won't be able to support Ventana's panel in 3.8 unless the > power sequences code gets merged for 3.8; is that likely? > -- > To unsubscribe from this list: send the line "unsubscribe linux-tegra" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >