On Wed, Dec 11, 2013 at 10:54:01PM +0000, Liviu Dudau wrote: > 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 > Hi Warren, Just to let you know, I've managed to get output working. Using the Atrix Lapdock, I've had to connect the special USB cable as well (data, no power) in order for the monitor to work. The strange thing is that on both monitors that I have tested I get the default list of modelines that includes 1024x768. The Lapdock disconnects after a few seconds, but with USB plugged in it comes back and reports the correct resolutions. Thanks for your time, and sorry for the noise. Best regards, 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
