mx53 qsb dual output: hdmi kills ethernet

[koobla]

Hi all,

I have set up my qsb over the last few days and it works nicely with the mcimx-lvds1 and vga output in dual and separate modes (imx-2.6.35_11.09 plus the  201112 patches applied). It boots nicely with the standard tftp+nfs setup until the HDMI daughter board arrived (I need to setup HDMI+LVDS, independent views):

Whenever I try to enable HDMI output with LVDS (tried with LVDS attached, without LVDS, widh and without DVI / HDMI monitors), the kernel does not boot into user space as initializing the ethernet controller fails. It does boot into the mmc image, though - cf. the boot log that I attached.

Kernel command line: console=tty1 console=ttymxc0,115200 setenv bootargs console=ttymxc0,115200 video=mxcdi0fb:RGB24,1024x768M@60 hdmi di0_primary video=mxcdi1fb:RGB24,1024x768M@60 ldb=di0 lvds debug loglevel=8 dmfc=3

I already started tracing signal lines on the daughter board to see if there could be any conflicts, but no luck so far.

Any ideas on this?

Simon

Original Attachment has been moved to: boot.txt.zip

[jimmychan]

When hdmi is using di0, lvds should use the di1 (ldb=1). But there is a limitation on the QSB hardware. The lvds1 signals didn't link to the lvds port. (read the QSB schematic fro details). So the HDMI + LVDS cannot work on the QSB.

[koobla]

Hi Jimmy,
actually, I had hoped that it would be possible; the LDB_CTRL register suggests that it would be possible to use DI1 for LVDS channel 0 -- somehow I overlooked the channel mapping table in refman chapter 47.4.1.

As a workaround, would it work to drive both channels from DI1, even if lvds1 is not connected? Does this imply a severe power consumption penalty?
thanks for the insights

Simon

[jimmychan]

I asked the expert about this issue. please try to add "ldb=di1,dual".

[koobla]

I tried the following:

setenv bootargs_base 'setenv bootargs console=ttymxc0,115200 video=mxcdi0fb:RGB666,XGA video2=mxcdi1fb:RGB666,XGA ldb=dual,di=1 loglevel=8'

run bootcmd_net

the kernel does not even show the early console, but the bootloader is frozen after ('Starting kernel') - if i deactivate the ldb=dual,di=1 it boots normally, but I don't see how the hdmi encoder could freeze the whole system.

Are there any improvements in the Android branch? or in a fsl git branch? Is my board broken?  I can try anything that does not involve a HW JTAG...

Slightly puzzled,

Simon

[daiane_angolini]

This is the latest kernel we have for imx53QSB (and I believe it will work to Android as well)

http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/log/?h=imx_2.6.35_11.09.01

Please, take a look if your kernel is latest.

I did not understand what you mean by "As a workaround, would it work to drive both channels from DI1, even if lvds1 is not connected?"

Could you, please, elaborate?

[koobla]

Hi Daiane,

the ldb block can receive input from either di0 or di1 (or both); the register definition suggests that both lvds outputs can read from either channel, but the channel mapping table in the reference manual shows that when DI1 is read, the output can only be routed to  lvds1 (single/separate mode), but not to lvds0 ; this is only possible in dual mode, where the input from di1 is duplicated to lvds0 and lvds1.

At least in theory, as my board freezes. As I learned from my partners who use a Digi ConnectCore module, this setup actually works for them.

[daiane_angolini]

I understand, you mean, display the same content (from di1) on two output (lvds0 AND lvds1)

Do you have both hardware lvds connected? Or are you trying only measuring using a scope at first?

[koobla]

lvds0 is connected to the mcimx-lvds1, lvds1 is n.c.; I am a software guy, i fear :smileywink:, and my scope doesn't have the bandwidth (SeedStudio DSO Quad, 70MHz). Could well be that I created a radio transmitter...

Simon

[daiane_angolini]

I´m a software girl as well, but your kernel would work in my point of view, unless you had messed your hardware some way.

Maybe, you could review your goal. In order to make sure you´re going to the right direction trying dual display with two LVDS´s using QSB board.

[koobla]

So it boils down to the unconnected LVDS port it seems - could someone in this community try to replicate the behavior on her/his board? I would be interested to see if this is systematic or a board problem (i.e. -> RMA)

many thanks

[koobla]

Seems it's a hw issue after all; I removed the hdmi board, the lvds hangs the kernel whenever I activate dual mode - no matter if I use di0 or di1 ; finally, " ldb=single,di=1 " has the same effect.

[daiane_angolini]

by "kernel would work" I mean, it would load until the console, at least....

[jimmychan]

Have you try "ldb=di1,dual" ?  not "ldb=dual,di=1".