I've been trying to get a dual display working on the i.MX6QP (EDM1 Fairy). I've a 1024x768 lcd display connected to mxcfb0, and a hdmi display connected to mxcfb1. I've got output on both displays, however I ideally want to configure the hdmi display to 800x600 (svga), but the screen flickers on/off intermittently, anywhere between 0.5/2/3 secs.
Interestingly, we've tried the hdmi output to four different monitors, and they all exhibit this apparent switching on/off (blanking) except for a particular HP display, which appears to work fine.
I have added the following to mxc_edid.c,
/* #61: 800x600@60Hz 4:3 */
[61] = {
NULL, 60, 800, 600, 25132, 88, 40, 23, 1, 128, 4,
FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
FB_VMODE_NONINTERLACED | FB_VMODE_ASPECT_4_3, 0
},
and to mxc_edid.c:
/* 800x600@60Hz 4:3 */
{
NULL, 60, 800, 600, 25132, 88, 40, 23, 1, 128, 4,
FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
FB_VMODE_NONINTERLACED | FB_VMODE_ASPECT_4_3, FB_MODE_IS_VESA,
},
and rebuilt the kernel! cat /sys/class/graphics/fb2/modes displays these new modes I added, prefixed with a 'V:'. As an aside, what does the 'V:' indicate?
If I configure the hdmi display (mxcfb1 in uEnv.txt) to 1920x1080@60, or 1024x768@60, the display is fine.
Should it be possible to configure the hdmi output for 800x600?
The display is connected to a Samsung UHD monitor, which is capable of 800x600 graphics according to the documentation (http://downloadcenter.samsung.com/content/um/201906/20190620124434612/bn46-00904a-eng.pdf ).
TIA.
