On Wed, Dec 11, 2013 at 03:17:23PM -0700, Stephen Warren wrote: > On 12/11/2013 02:49 PM, Liviu Dudau wrote: > > Hello, > > > > Prompted by a discussion on G+, here is a report of an issue I'm seeing > > with mainline kernel (commit 78fd82238d0e57). > > > > The kernel fails to detect the DDC i2c interface (on Trimslice that's > > on Tegra2 I2C-0 interface), so I'm getting no output on the HDMI > > That probably should be I2C-1 for HDMI; I2C-0 is likely the DVI port's > DDC interface. But since you tested all ports, this isn't the cause of > the problem. Sorry, I had the Trimslice manual opened on the other screen while I was composing the email and I've read the wrong paragraph. You are correct, it is connected to I2C-1. > > > U-Boot 2014.01-rc1-dirty (Nov 26 2013 - 22:29:37) > > Are you using an unmodified upstream U-Boot? The environment you posted > doesn't match upstream's environment, and the "-dirty" implies you have > some local modifications. Yes, the U-Boot is upstream, the only change being the removal of some artefact from boards.cfg that got commited a while ago. The environment is a streamlined version that I've comed up with as I didn't like the whole scanning for u-boot scripts. > > If you break into U-Boot, can you read the EDID using the "i2c" command? Ughh, another one of the ugly, not properly documented set of U-Boot commands. I need to read on the documentation to learn how to use it (what's the muxaddr for tegra2?). > > In Linux, can you "i2cget" from bus 1 device 0x50 even if "i2cdetect" > didn't see the EDID? # i2cget -y 1 0x50 Error: Read failed. > > Is the monitor you have plugged in known-working without any > EDID-related issues? I've tried another one as well (an Atrix Lapdock), no success. The current one is connected over an 4-to-1 box and my PC is happy to read the EDID off it using the radeon driver. Could you send me a log of your kernel booting with i2c being detected? I want to compare with mine just in case there might be some config options that I might have selected as modules and they don't get properly loaded. Many thanks, Liviu > -- > To unsubscribe from this list: send the line "unsubscribe linux-tegra" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
