HDMI 2.1 Quick Media Switching

[joops75]

I've noticed that the EDID reader at https://people.freedesktop.org/~imirkin/edid-decode/ can detect if a display has HDMI QMS. Its source code at https://git.linuxtv.org/v4l-utils.git/tr...-block.cpp reveals how this is done (edited here to just show the QMS parts):

Code:

void edid_state::cta_hf_scdb(const unsigned char *x, unsigned length)
{
    if (x[4] & 0x40)
        printf("    Supports QMS\n");
    if (x[7] & 0x20)
        printf("    Supports QMS TFRmax\n");
    if (x[7] & 0x10)
        printf("    Supports QMS TFRmin\n");
}

It would be cool if HDMI QMS read/write capabilities were added to CRU!

[ToastyX]

It will be in the rewrite coming later this year among other things.

[joops75]

(07-29-2025 02:42 AM)ToastyX Wrote:  It will be in the rewrite coming later this year among other things.

Looking forward to it!

For what it's worth, I discovered that the latest source code at https://git.linuxtv.org/v4l-utils.git/tr...id-decode/ is actually implemented at https://hverkuil.home.xs4all.nl/edid-dec...code.html. The URL I mentioned before implements an older version which does not detect HDMI QMS at time of writing.