Dev1 Galaxy Forum / Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (deepforest) — Fri, 18 Sep 2026 21:10:10 +0000

That's 2056px not 2560px horizontal. That'll work but it's not the native resolution of the monitor.

Indeed. Thanks. I am was tired and miss out this.

Also found this
https://wiki.archlinux.org/title/ATI#QH … deon_cards

Older cards have their pixel clock limited to 165MHz for HDMI. Hence, they do not support QHD or 4k only via dual-link DVI but not over HDMI.

The patch introduces a new kernel parameter radeon.hdmimhz which alters the pixel clock limit.

So, both Ati\Radeon and Nvidia have limits 165MHz?
Why this still not fixed at opensource drivers?
https://bugzilla.kernel.org/show_bug.cgi?id=172421

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (Mercury) — Thu, 17 Sep 2026 23:33:06 +0000

That's 2056px not 2560px horizontal. That'll work but it's not the native resolution of the monitor.

You can try the native resolution with 30Hz (nonstandard) or 40Hz (very nonstandard).

xrandr --newmode "2560x1440_30.00"  119.217 2560 2608 2640 2720 1440 1443 1448 1461 +hsync -vsync
xrandr --addmode HDMI-0 "2560x1440_30.00"

xrandr --newmode "2560x1440_40.00"  159.609 2560 2608 2640 2720 1440 1443 1448 1467 +hsync -vsync
xrandr --addmode HDMI-0 "2560x1440_40.00"

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (deepforest) — Thu, 17 Sep 2026 21:32:03 +0000

As here mentioned author of AMD Patcher Utility for Windows, HDMI port at Linux lose half pixels

The patch changes that to 230 MHz, but I don't have a patch for Linux. You do need an active adapter to go beyond 165 MHz pixel clock. The other option is to reduce the refresh rate to 50 Hz to get under 165 MHz.

https://www.monitortests.com/forum/Thre … 5#pid10625
So, i am apply that working mode

./cvt12 2056 1440 50 -b
# 2056x1440 @ 50.000 Hz Reduced Blank (CVT) field rate 50.000 Hz; hsync: 73.700 kHz; pclk: 157.42 MHz
Modeline "2056x1440_50.00_rb2"  157.42  2056 2064 2096 2136  1440 1460 1468 1474 +hsync -vsync

xrandr --newmode "2056x1440_50.00_rb2"  157.42  2056 2064 2096 2136  1440 1460 1468 1474 +hsync -vsync
xrandr --addmode HDMI-0 "2056x1440_50.00_rb2"
xrandr --output HDMI-0 --mode "2056x1440_50.00_rb2"

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (deepforest) — Thu, 17 Sep 2026 11:09:07 +0000

Did you mean not working?

mean not, thanks

I'm close to certain EDID is not the problem so patching it will do nothing.

i am unsure too, also patching EDID can be destructive

I notice the modelines you used are for 50Hz. Try the 60Hz from my post. Probably won't work, but just to confirm.

i will try and inform here

ps some interesting info here
https://www.monitortests.com/forum/Thre … 2#pid13742

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (Mercury) — Thu, 17 Sep 2026 02:26:36 +0000

also now working

,
Did you mean not working?

I'm close to certain EDID is not the problem so patching it will do nothing.

I notice the modelines you used are for 50Hz. Try the 60Hz from my post. Probably won't work, but just to confirm.

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (deepforest) — Thu, 17 Sep 2026 00:34:24 +0000

Hi, thanks for reply)

Mercury wrote:

How exactly are you using these?

When i try to add custom mode via "cvt", or "cvt12" i have "No signal" at monitor

xrandr --newmode "2560x1440_50.00_rb1"  200.25  2560 2608 2640 2720  1440 1443 1448 1474 +hsync -vsync
xrandr --addmode HDMI-0 "2560x1440_50.00_rb1"

xrandr --newmode "2560x1440_50.00_rb2" 194.57  2560 2568 2600 2640  1440 1460 1468 1474 +hsync -vsync
xrandr --addmode HDMI-0 "2560x1440_50.00_rb2"

Mercury wrote:

HDMI 1.3 officially has a max pixel clock of 340MHz so this monitor's desired clock (241.5Mhz) should be supportable

That why i am asking.
Its part of X log here mentioned 2560x1440 mode and clock of 340MHz

(--) RADEON(0): HDMI max TMDS frequency 340000KHz
(II) RADEON(0): EDID vendor "GBT", prod id 10056
(II) RADEON(0): Using hsync ranges from config file
(II) RADEON(0): Using vrefresh ranges from config file
(II) RADEON(0): Printing DDC gathered Modelines:
(II) RADEON(0): Modeline "2560x1440"x0.0  241.50  2560 2608 2640 2720  1440 1443 1448 1481 +hsync -vsync (88.8 kHz eP)
(II) RADEON(0): Modeline "2560x1440"x0.0  497.75  2560 2608 2640 2720  1440 1443 1448 1525 +hsync -vsync (183.0 kHz e)

This link to full X log
https://pastebin.com/raw/pfAfRrmv

PS
also answer from Artix forum

Don't bother with setting it through xorg, this won't work. You need to patch EDID directly.

but its unsafe and i am do not want do that

PPS
also if i try set custom EDID(i am grub bin from get-edid command) via kernel boot option its also not working.

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (Mercury) — Wed, 16 Sep 2026 16:21:28 +0000

deepforest wrote:

When i am try apply custom modes using cvt or cvt12 i get "No signal" from monitor?

How exactly are you using these?

Maybe it opensource Radeon driver issue?

Possibly.

HDMI 1.3 officially has a max pixel clock of 340MHz so this monitor's desired clock (241.5Mhz) should be supportable.

The EDID does not seem to be the issue. What does a plain xrandr output? Is 2560x1440 available?

Have you tired adding a custom mode using xrandr?

# 1. Define the new mode using the CVT-RB parameters
xrandr --newmode "2560x1440_60.00"  241.50  2560 2608 2640 2720  1440 1443 1448 1481 +hsync -vsync

# 2. Assign the mode to your active display output
xrandr --addmode HDMI-0 "2560x1440_60.00"

# 3. Switch the display to the new resolution
xrandr --output HDMI-0 --mode "2560x1440_60.00"

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (deepforest) — Mon, 07 Sep 2026 23:17:06 +0000

here Xorg.log
https://pastebin.com/raw/FycJuncx

Re: Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (deepforest) — Mon, 07 Sep 2026 22:59:48 +0000

Any ideas?
I am do not understand where is can be issue here?

My monitor have 2 x HDMI 2.0

Connectivity

Information about the available connectivity ports, slots and interfaces such as USB, infrared port, SD card slot, audio/video and network interfaces, etc.
	1 x USB 2.0 (Type-A; downstream; FW update only)
2 x HDMI 2.0
1 x DisplayPort 1.4 (DSC)
1 x 3.5 mm Audio Out

https://www.displayspecifications.com/en/model/9dd44578

My video car have 1x HDMI 1.3a

Outputs
    2x DVI
    1x HDMI 1.3a
    1x DisplayPort 1.1

https://www.techpowerup.com/gpu-specs/r … -5770.c250

So.
According to this article on Wikipedia, it Max. TMDS character rate (MHz) 340
https://en.wikipedia.org/wiki/HDMI#Version_comparison

Here can not be limits 165MHz
https://www.monitortests.com/forum/Thre … 5#pid10625

Why by default Linux open Radeon driver not detect 2K mode at 60Hz?
When i am try apply custom modes using cvt or cvt12 i get "No signal" from monitor?

Maybe it opensource Radeon driver issue?

Radeon HD 5770 at G27Q20 monitor, how set 2560x1440 mode?

dummy@example.com (deepforest) — Thu, 03 Sep 2026 19:26:12 +0000

Hi!)
At my new 2K monitor i cant set 2560x1440 via hdmi
i am understand that limitation of hdmi specs at Radeon HD 5770

Video features
Multi-monitor:	Up to 4 displays
Maximum digital resolution:	2560 x 1600
Maximum DP resolution:	2560 x 1600
Maximum DVI resolution:	2560 x 1600
Maximum HDMI resolution:	1920 x 1200
Maximum VGA resolution:	2048 x 1536
Anti-Aliasing technologies:	24 x MSAA
24 x SSAA
Adaptive AA
HDMI:	Yes
HDMI version:	1.3

https://www.gpuzoo.com/GPU-ATI/Radeon_HD_5770.html

But under Windows i am apply this patch and can set 2k mode with no issues
https://www.monitortests.com/forum/Thre … ck-Patcher

Is there similar bypass at Linux for set 2k resolution?

ps is it safe if i try use DVI > HDMI adapter for setup 2k resolution here via dvi?

root@devuan:/home/freeartist-devuan# xrandr --prop | edid-decode
edid-decode (hex):

00 ff ff ff ff ff ff 00 1c 54 48 27 01 01 01 01
0d 23 01 03 80 3c 22 78 ee e6 f5 aa 53 47 a6 24
0c 50 54 bf ef 80 71 4f 81 c0 81 00 81 40 81 80
95 00 d1 fc b3 00 56 5e 00 a0 a0 a0 29 50 30 20
35 00 55 50 21 00 00 1a 00 00 00 fd 00 30 c8 1e
e6 3c 00 0a 20 20 20 20 20 20 00 00 00 fc 00 47
32 37 51 32 30 0a 20 20 20 20 20 20 00 00 00 ff
00 0a 20 20 20 20 20 20 20 20 20 20 20 20 01 67

02 03 4c f1 e2 78 02 4e 03 02 04 0f 10 12 11 13
1f 20 29 3f 40 61 23 09 07 07 83 01 00 00 67 03
0c 00 10 00 38 44 6a d8 5d c4 01 78 88 01 01 30
90 68 1a 00 00 01 01 30 90 e6 e3 05 c3 01 e3 0f
00 20 e6 06 0d 01 65 65 1c e2 00 ea 6f c2 00 a0
a0 a0 55 50 30 20 35 00 55 50 21 00 00 1a 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 d9

----------------

Block 0, Base EDID:
  EDID Structure Version & Revision: 1.3
  Vendor & Product Identification:
    Manufacturer: GBT
    Model: 10056
    Serial Number: 16843009
    Made in: week 13 of 2025
  Basic Display Parameters & Features:
    Digital display
    Maximum image size: 60 cm x 34 cm
    Gamma: 2.20
    DPMS levels: Standby Suspend Off
    RGB color display
    Default (sRGB) color space is primary color space
    First detailed timing is the preferred timing
  Color Characteristics:
    Red  : 0.6669, 0.3261
    Green: 0.2783, 0.6503
    Blue : 0.1435, 0.0498
    White: 0.3134, 0.3291
  Established Timings I & II:
    IBM     :   720x400    70.081663 Hz   9:5     31.467 kHz     28.320000 MHz
    DMT 0x04:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    Apple   :   640x480    66.666667 Hz   4:3     35.000 kHz     30.240000 MHz
    DMT 0x05:   640x480    72.808802 Hz   4:3     37.861 kHz     31.500000 MHz
    DMT 0x06:   640x480    75.000000 Hz   4:3     37.500 kHz     31.500000 MHz
    DMT 0x08:   800x600    56.250000 Hz   4:3     35.156 kHz     36.000000 MHz
    DMT 0x09:   800x600    60.316541 Hz   4:3     37.879 kHz     40.000000 MHz
    DMT 0x0a:   800x600    72.187572 Hz   4:3     48.077 kHz     50.000000 MHz
    DMT 0x0b:   800x600    75.000000 Hz   4:3     46.875 kHz     49.500000 MHz
    Apple   :   832x624    74.551266 Hz   4:3     49.726 kHz     57.284000 MHz
    DMT 0x10:  1024x768    60.003840 Hz   4:3     48.363 kHz     65.000000 MHz
    DMT 0x11:  1024x768    70.069359 Hz   4:3     56.476 kHz     75.000000 MHz
    DMT 0x12:  1024x768    75.028582 Hz   4:3     60.023 kHz     78.750000 MHz
    DMT 0x24:  1280x1024   75.024675 Hz   5:4     79.976 kHz    135.000000 MHz
    Apple   :  1152x870    75.061550 Hz 192:145   68.681 kHz    100.000000 MHz
  Standard Timings:
    DMT 0x15:  1152x864    75.000000 Hz   4:3     67.500 kHz    108.000000 MHz
    DMT 0x55:  1280x720    60.000000 Hz  16:9     45.000 kHz     74.250000 MHz
    DMT 0x1c:  1280x800    59.810326 Hz  16:10    49.702 kHz     83.500000 MHz
    DMT 0x20:  1280x960    60.000000 Hz   4:3     60.000 kHz    108.000000 MHz
    DMT 0x23:  1280x1024   60.019740 Hz   5:4     63.981 kHz    108.000000 MHz
    DMT 0x2f:  1440x900    59.887445 Hz  16:10    55.935 kHz    106.500000 MHz
    GTF     :  1920x1080  119.999987 Hz  16:9    138.840 kHz    368.759000 MHz
    DMT 0x3a:  1680x1050   59.954250 Hz  16:10    65.290 kHz    146.250000 MHz
  Detailed Timing Descriptors:
    DTD 1:  2560x1440   59.950550 Hz  16:9     88.787 kHz    241.500000 MHz (597 mm x 336 mm)
                 Hfront   48 Hsync  32 Hback   80 Hpol P
                 Vfront    3 Vsync   5 Vback   33 Vpol N
    Display Range Limits:
      Monitor ranges (GTF): 48-200 Hz V, 30-230 kHz H, max dotclock 600 MHz
    Display Product Name: 'G27Q20'
    Display Product Serial Number: ''
  Extension blocks: 1
Checksum: 0x67

----------------

Block 1, CTA-861 Extension Block:
  Revision: 3
  Underscans IT Video Formats by default
  Basic audio support
  Supports YCbCr 4:4:4
  Supports YCbCr 4:2:2
  Native detailed modes: 1
  HDMI Forum EDID Extension Override Data Block:
    EDID Extension Block Count: 2
  Video Data Block:
    VIC   3:   720x480    59.940060 Hz  16:9     31.469 kHz     27.000000 MHz
    VIC   2:   720x480    59.940060 Hz   4:3     31.469 kHz     27.000000 MHz
    VIC   4:  1280x720    60.000000 Hz  16:9     45.000 kHz     74.250000 MHz
    VIC  15:  1440x480    59.940060 Hz  16:9     31.469 kHz     54.000000 MHz
    VIC  16:  1920x1080   60.000000 Hz  16:9     67.500 kHz    148.500000 MHz
    VIC  18:   720x576    50.000000 Hz  16:9     31.250 kHz     27.000000 MHz
    VIC  17:   720x576    50.000000 Hz   4:3     31.250 kHz     27.000000 MHz
    VIC  19:  1280x720    50.000000 Hz  16:9     37.500 kHz     74.250000 MHz
    VIC  31:  1920x1080   50.000000 Hz  16:9     56.250 kHz    148.500000 MHz
    VIC  32:  1920x1080   24.000000 Hz  16:9     27.000 kHz     74.250000 MHz
    VIC  41:  1280x720   100.000000 Hz  16:9     75.000 kHz    148.500000 MHz
    VIC  63:  1920x1080  120.000000 Hz  16:9    135.000 kHz    297.000000 MHz
    VIC  64:  1920x1080  100.000000 Hz  16:9    112.500 kHz    297.000000 MHz
    VIC  97:  3840x2160   60.000000 Hz  16:9    135.000 kHz    594.000000 MHz
  Audio Data Block:
    Linear PCM:
      Max channels: 2
      Supported sample rates (kHz): 48 44.1 32
      Supported sample sizes (bits): 24 20 16
  Speaker Allocation Data Block:
    FL/FR - Front Left/Right
  Vendor-Specific Data Block (HDMI), OUI 00-0C-03:
    Source physical address: 1.0.0.0
    DC_36bit
    DC_30bit
    DC_Y444
    Maximum TMDS clock: 340 MHz
  Vendor-Specific Data Block (HDMI Forum), OUI C4-5D-D8:
    Version: 1
    Maximum TMDS Character Rate: 600 MHz
    SCDC Present
    Supports scrambling for <= 340 Mcsc
    Supports 10-bits/component Deep Color 4:2:0 Pixel Encoding
    Supports a FAPA in blanking after first active video line
    VRRmin: 48 Hz
    VRRmax: 144 Hz
  Vendor-Specific Data Block (AMD), OUI 00-00-1A:
    Version: 1.1
    Minimum Refresh Rate: 48 Hz
    Maximum Refresh Rate: 144 Hz
    Flags 1.x: 0xe6 (MCCS)
  Colorimetry Data Block:
    xvYCC601
    xvYCC709
    BT2020YCC
    BT2020RGB
    Reserved MD0
  YCbCr 4:2:0 Capability Map Data Block:
    VIC  97:  3840x2160   60.000000 Hz  16:9    135.000 kHz    594.000000 MHz
  HDR Static Metadata Data Block:
    Electro optical transfer functions:
      Traditional gamma - SDR luminance range
      SMPTE ST2084
      Hybrid Log-Gamma
    Supported static metadata descriptors:
      Static metadata type 1
    Desired content max luminance: 101 (445.755 cd/m^2)
    Desired content max frame-average luminance: 101 (445.755 cd/m^2)
    Desired content min luminance: 28 (0.054 cd/m^2)
  Video Capability Data Block:
    YCbCr quantization: Selectable (via AVI YQ)
    RGB quantization: Selectable (via AVI Q)
    PT scan behavior: Always Underscanned
    IT scan behavior: Always Underscanned
    CE scan behavior: Always Underscanned
  Detailed Timing Descriptors:
    DTD 2:  2560x1440  119.997589 Hz  16:9    182.996 kHz    497.750000 MHz (597 mm x 336 mm)
                 Hfront   48 Hsync  32 Hback   80 Hpol P
                 Vfront    3 Vsync   5 Vback   77 Vpol N
Checksum: 0xd9
root@devuan:/home/freeartist-devuan#