AnsweredAssumed Answered

i.MX6 HDMI blanks out

Question asked by Robert McLean on Mar 25, 2020
Latest reply on Mar 27, 2020 by igorpadykov

I've been working on a modification to the mxc_ipuv3 frame buffer driver to clone one display to another by using the IC block in the IPU to scale and center the source frame buffer on the destination frame buffer.  The modifications to the driver are basically working.  It does clone an LVDS (resolution 1024x600) to an HDMI (1080p), and the image on the HDMI is scaled so that the vertical resolutions match, and scaled image is centered on the HDMI screen.  The modification only actively clones the source frame buffer while the device file for the source is open.  When the driver is not actively cloning (ie no one is using the source framebuffer) there is no problem with the HDMI. 


However, occasionally while the driver is actively cloning, the HDMI will intermittently go dark. While it is dark, the HDMI monitor tells me there is no signal.  It is as if the HDMI phy has shut off.


I'm also noticing while this is happening, the temperature of the CPU is ~60C as reported by:

cat /sys/class/thermal/thermal_zone0/temp

Is there a thermal limit on the HDMI phy? 


If not I'm wondering what else could be causing this intermittent shutdown of the HDMI signal from my i.MX6DQ?