AMD Radeon HD 7470M not able to display 2560x1080
System information
- OS: Ubuntu 20.04 LTS
- GPU: AMD Radeon HD 7470M. Advanced Micro Devices, Inc. [AMD/ATI] Seymour [Radeon HD 6400M/7400M Series]
- Kernel version:
Linux pc 5.4.0-26-generic #30-Ubuntu SMP Mon Apr 20 16:58:30 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
- Mesa version:
OpenGL version string: 3.1 Mesa 20.1.0-devel (git-bf3c9d2 2020-04-25 focal-oibaf-ppa)
- Xserver version (if applicable): X.Org X Server 1.20.8
Issue description
I am using a external monitor LG Ultrawide 25um58-p and the issue is that I cannot use the maximum resolution of this screen, which should be 2560x1080. I have seen many questions and answers related to ultrawide monitors but none of the answers has worked for me. So far I have tried to add a custom resolution by:
$ cvt 2560 1080 60
# 2560x1080 59.98 Hz (CVT) hsync: 67.17 kHz; pclk: 230.00 MHz
Modeline "2560x1080_60.00" 230.00 2560 2720 2992 3424 1080 1083 1093 1120 -hsync +vsync
$ xrandr --newmode "2560x1080_60.00" 230.00 2560 2720 2992 3424 1080 1083 1093 1120 -hsync +vsync
$ xrandr --addmode HDMI-0 "2560x1080_60.00"
$ xrandr --output HDMI-0 --mode 2560x1080_60.00
I have also tried this 2560x1080 resolution with different frequencies (from 40Hz to 65Hz) calculating the modeline with cvt and also using reduce blanking (cvt -r). I have also tried the Modeline that seems to be used when I use this monitor in Windows 10:
"2560x1080_60.00" 185.58 2560 2624 2688 2784 1080 1083 1093 1111 -hsync -vsync
However, none of the previous modelines has worked and I always get one of the following errors:
- Blank screen
- Blurry/shaky image (see attachment)
- Laptop screen crashed and second monitor blurry (as previous case)
So far the most I have manage to do is using 2160x900 resolution so at least I have 21:9 aspect ratio. This has worked for me even though is not the solution I am after:
$ cvt 2160 900 60
# 2160x900 59.91 Hz (CVT) hsync: 55.95 kHz; pclk: 160.25 MHz
Modeline "2160x900_60.00" 160.25 2160 2288 2512 2864 900 903 913 934 -hsync +vsync
$ xrandr --newmode "2160x900_60.00" 160.25 2160 2288 2512 2864 900 903 913 934 -hsync +vsync
$ xrandr --addmode HDMI-0 "2160x900_60.00"
$ xrandr --output HDMI-0 --mode 2160x900_60.00
I have used 2560x1080 with the same laptop using Windows 10 so I assume the graphic card should be able to handle so I would assume it is an issue with the drivers.
Regression
Did it used to work? - It's the first time I connect this screen so never tried ultrawide resolution before.