how do android automaticly adapt to HDMI monitor?

[murphy1]

now i have a problem about HDMI output in IMX6,

i set default HDMI output to 1280*1024 in boot env(l have already add 1280*1024 surpport in  mxc_edid.c),then i connect to a monitor that support 1280*1024,all is OK;but when i connect to a monitor that dont support 1280*1024,i find that the HDMI dirver in kernel change to 1280*720 to adapt to the monitor,but then the monitor cant display normally the whole desktop in Android,it's like that android still use 1280*1024 although the HDMI driver already set to 1280*720.

ps:  the SDK i used is Android 4.4.2,linux kernel is 3.0.15.

so how to solve this problem?

[igorpadykov]

Hi  murphy

one can debug it using link to app note below and Chapter 11
HDMI Driver attached Linux Manual, check if monitor correctly sent parameters to driver

for required resolution. May be useful to try with other monitor.

AN4553 Using Open Source Debugging Tools for Linux on i.MX Processors
http://www.nxp.com/assets/documents/data/en/application-notes/AN4553.pdf

Best regards
igor
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[murphy1]

thanks for your reply. i have print the monitor's EDID log ,so i'm sure that the monitor dont support 1280*1024. my question is that for example if one monitor just support 1280*1024 type,another just support 1280*720 type,if i connect to these monitor alterlately ,the android screen output will be unnormal.

so it seems  the imx6 android BSP dont support diffirent HDMI output resolution dynamicly,and that is what i want to  confirm with NXP.   if so how to fix this ?

[igorpadykov]

please refer to sect.11.2.4 Hotplug Handling and Video Mode Changes

attached in first answer Linux Manual

Best regards
igor