Bug 6703

Summary: Kernel hangs on boot when HDMI cable is plugged
Product: [Build System, Metadata & Runtime] BSPs Reporter: Daiane <angolini>
Component: bsps-meta-fsl-armAssignee: Otavio Salvador <otavio>
Status: RESOLVED FIXED QA Contact:
Severity: critical    
Priority: Medium CC: martin.hintermann, picmaster, richard.purdie
Version: unspecified   
Target Milestone: Future   
Hardware: Other   
OS: arm   
Whiteboard:
OS type for building Yocto: --- Type of Regression: ---
Verified: Documentation change: No (bug/feature does not impact docs)

Description Daiane 2014-09-09 17:05:06 UTC 
If HDMI cable is plugged during the reset/boot process, kernel hangs at the beginning.

If kernel is loaded, and then the cable is inserted, no problem.

It was reproduced with imx6dlsabresd and imx6qsabresd,
kernel: 3.10.17-1.0.1_ga+gdac46c
u-boot: 2014.07+fslc+ga824e89
Comment 2 Daiane 2014-09-13 00:44:44 UTC 
A workaround for this would be using the following command line in u-boot

=> setenv panel Hannstar-XGA

to avoid the splash screen to be re-directed to HDMI, forcing it to be always on LDVS

However it does not fix the kernel crash, only avoid it.
Comment 3 Nikolay Dimitrov 2014-11-13 23:14:29 UTC 
As discussed on the ML, there's another possible work-around (thanks to Fabio). 
Here are the steps to implement it on imx6q sabresd:

1. Disable the HDMI support in u-boot-fsl, rebuild U-Boot, write the new bootloader on the sdcard.
2. Add your video bootargs to "mmcarg" U-Boot env-var via "editenv mmcarg":

video=mxcfb0:dev=hdmi,1280x720M@60,if=RGB24

3. "setenv mmcdev 0" if you're booting from SD2, otherwise skip to 4.
4. "run bootcmd".
5. Observe that Xorg is now visible on the HDMI screen.

HDMI cable can be either connected during power-on, or attached later. In both cases HDMI video will work properly.

As already stated above, this is just a practical work-around and it doesn't solve the original issue.
Comment 4 Nikolay Dimitrov 2014-11-14 11:00:46 UTC 
> 2. Add your video bootargs to "mmcarg" U-Boot env-var via "editenv mmcarg":

"mmcarg" should be actually "mmcargs".
Comment 5 Daiane 2015-10-21 16:50:11 UTC 
It is working now (jethro) with u-boot 2015.10 (at least)