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XeCycle

Member

Registered: 2011-03-29

Posts: 13

Can freesync monitors work in 48Hz with Intel graphics?

Background: I want a display with support for refresh rates at multiples of 24fps (or 23.98fps) to fix stuttering when playing such videos.

I saw some freesync-capable monitors advertised a range of 48~70Hz, which should be good enough for my use case, and not too heavy to drive for Intel GFX like those 120Hz ones.  So can I use such monitors in this way?  Do they advertise such rates to xrandr, or do I need to manually add such undetected rates (and be guaranteed that it works)?

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 15,102

Re: Can freesync monitors work in 48Hz with Intel graphics?

https://wiki.archlinux.org/index.php/Va … fresh_rate

https://www.intel.com/content/www/us/en … brief.html

https://software.intel.com/en-us/articl … -microsoft

Maybe Ice Lake does support freesync, older intel processors clearly don't.

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XeCycle

Member

Registered: 2011-03-29

Posts: 13

Re: Can freesync monitors work in 48Hz with Intel graphics?

...
Maybe Ice Lake does support freesync, older intel processors clearly don't.

Thanks; I am aware that older processors (mine i7 7700) do not support that.  I wonder if they can support running in "fixed" rates at, e.g., 48Hz, 50Hz, etc.

Ropid

Member

Registered: 2015-03-09

Posts: 1,069

Re: Can freesync monitors work in 48Hz with Intel graphics?

You will need to program that 48Hz mode yourself. It will not be advertised by the monitor.

Are you sure you need a FreeSync monitor for this? I don't see why it wouldn't work with any normal 60Hz monitor. Just try it with the monitor you are using right now, a custom 48Hz modeline will probably work fine.

Something about the modeline: check out the "cvt12-git" package from the AUR. What's interesting about it is that it can do "reduced blank" modes for refresh rates other than 60Hz. The normal "cvt" program that's in the xorg-server package can only do it for 60Hz. That cvt12 program also has interesting parameters to get that weird "23.976" number.

Here's two 1080p modelines created by that cvt12 program:

$ cvt12 1920 1080 48 -b -o
# 1920x1080 @ 48.000 Hz Reduced Blank (CVT) field rate 47.952 Hz; hsync: 52.987 kHz; pclk: 105.97 MHz
Modeline "1920x1080_48.00_rb2"  105.97  1920 1928 1960 2000  1080 1091 1099 1105 +hsync -vsync

$ cvt12 1920 1080 48 -b
# 1920x1080 @ 48.000 Hz Reduced Blank (CVT) field rate 48.000 Hz; hsync: 53.040 kHz; pclk: 106.08 MHz
Modeline "1920x1080_48.00_rb2"  106.08  1920 1928 1960 2000  1080 1091 1099 1105 +hsync -vsync

Here's two 1080p modelines for 72Hz (that's 24 times three). That kind of increase for the Hz works on some 60Hz monitors:

$ cvt12 1920 1080 72 -b -o
# 1920x1080 @ 72.000 Hz Reduced Blank (CVT) field rate 71.928 Hz; hsync: 80.344 kHz; pclk: 160.69 MHz
Modeline "1920x1080_72.00_rb2"  160.69  1920 1928 1960 2000  1080 1103 1111 1117 +hsync -vsync

$ cvt12 1920 1080 72 -b
# 1920x1080 @ 72.000 Hz Reduced Blank (CVT) field rate 72.000 Hz; hsync: 80.424 kHz; pclk: 160.85 MHz
Modeline "1920x1080_72.00_rb2"  160.85  1920 1928 1960 2000  1080 1103 1111 1117 +hsync -vsync

Last edited by Ropid (2019-10-15 14:00:29)

XeCycle

Member

Registered: 2011-03-29

Posts: 13

Re: Can freesync monitors work in 48Hz with Intel graphics?

... Just try it with the monitor you are using right now, a custom 48Hz modeline will probably work fine.
...

Thanks; tried it with mine (ASUS VS24AHL), when switched to 48Hz, it gave me an OSD saying "out of range".

EDIT: tried again with 72Hz, the same OSD.

Last edited by XeCycle (2019-10-15 14:41:57)

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 15,102

Re: Can freesync monitors work in 48Hz with Intel graphics?

Check your X.org.log for lines like these (1 per attached monitor) :

[   114.364] (II) AMDGPU(0): Ranges: V min: 48 V max: 85 Hz, H min: 24 H max: 94 kHz, PixClock max 175 MHz

Modelines with values for V , H and Pixel Clock outside of those ranges will fail.

The technical specifications  of a monitor often include these ranges, I've looked them up for your Asus VS24AHL .

Signal Frequency
Analog Signal Frequency : 30~83 KHz(H)/ 50~61 Hz(V)
Digital Signal Frequency : 30 ~83 KHz (H) /50 ~61 Hz(V)

All 4 modelines posted in #4 have a V outside of the supported 50-61 Hz range, so won't work.

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

clean chroot building not flexible enough ?
Try clean chroot manager by graysky