Created attachment 1800188 [details]
journalctl --no-hostname -k

1. Please describe the problem:

I have a 2k monitor, when connected to my Lenovo P1 gen3 laptop (CometLake-H GT2 UHD Graphic) with HDMI, the best resolution can be set is 1920x1440 or 2560x1080, the 2560x1440 resolution shows up in output of xrandr and display settings, but when set the monitor to 2560x1440, the external monitor just go blank and show "no signal".

2. What is the Version-Release number of the kernel:
5.12.14-300.fc34.x86_64

3. Did it work previously in Fedora?
No, this is a new laptop with fresh installed Fedora 34, but I tried an old kernel (kernel-5.10.21-200.fc33.x86_64), it doesn't work either.


4. Can you reproduce this issue? If so, please provide the steps to reproduce
   the issue below:
Yes.
1. Connect the external monitor via HDMI
2. Configure the external monitor to use resolution 2560x1440 in "Settings -> Display". 


5. Does this problem occur with the latest Rawhide kernel? To install the
   Rawhide kernel, run ``sudo dnf install fedora-repos-rawhide`` followed by
   ``sudo dnf update --enablerepo=rawhide kernel``:
Yes, can reproduce with kernel-core-5.14.0-0.rc0.20210701gitdbe69e433722.6.fc35.x86_64.

6. Are you running any modules that not shipped with directly Fedora's kernel?:
No.

7. Please attach the kernel logs. You can get the complete kernel log
   for a boot with ``journalctl --no-hostname -k > dmesg.txt``. If the
   issue occurred on a previous boot, use the journalctl ``-b`` flag.
log attached.

Additional info:
[1] # lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation CometLake-H GT2 [UHD Graphics] (rev 05)

[2] The firmware has been updated to latest version
├─System Firmware:
│ │   Device ID:          da99ffa7e037e614f6f43e730e9aedba0a603152
│ │   Current version:    0.1.16
│ │   Minimum Version:    0.1.0
│ │   Vendor:             LENOVO (DMI:LENOVO)

[3] Run the following command, the external monitor goes blank and shows "no signal":

# xrandr --output DP-1 --mode 2560x1440 --verbose
screen 0: 4480x1440 1186x381 mm  95.92dpi
crtc 1:    2560x1440  59.95 +1920+0 "DP-1"

Then with the following command, the external monitor is connected back:

# xrandr --output DP-1 --mode 2560x1080 --verbose
crtc 1: disable
screen 0: 4480x1080 1185x285 mm  96.00dpi
crtc 1:    2560x1080  60.00 +1920+0 "DP-1"

[4]dmesg (with drm.debug=0x116), xrandr, lspci output, xorg logs are attached.