Description of problem: On Hyper-V host, set gen1 VM MAX resolution > 3840x4320 (like 7680x4320), actually the supported maximum is 3840x4320, then start VM, sometimes gnome start failed(can access VM via ssh), sometimes VM start failed with kernel panic. Gen2 VM does not have this problem, it can support 7680x4320 This is to track https://bugzilla.redhat.com/show_bug.cgi?id=1941841#c62 Version-Release number of selected components (if applicable): Host: Hyper-V 2019 Guest: gen1 VM with 4.18.0-302.el8.x86_64 RHEL Version: RHEL-8.4 How reproducible: 100% Steps to Reproduce: 1. Power off gen1 VM, set resolution to 7680x4320 on Host with powershell command, actually gen1 does not support such big resolution c:\> Set-VMVideo RHEL-8.4-GEN1-B -HorizontalResolution 7680 -VerticalResolution 4320 -ResolutionType Maximum 2. Start VM with "video=hyperv_fb:1920x1080" Actual results: 1) GUI starts failed with logs [ 16.993689] hv_vmbus: registering driver hyperv_fb [ 17.009207] hyperv_fb: Synthvid Version major 3, minor 5 [ 17.009249] hyperv_fb: Screen resolution: 1920x1080, Color depth: 32 [ 17.009253] hyperv_fb: Unable to allocate enough contiguous physical memory on Gen 1 VM. Using MMIO instead. [ 17.009254] hyperv_fb: Resource not available or (0x4000000 < 0x8000000) [ 17.009254] hyperv_fb: No memory for framebuffer [ 17.009576] hv_vmbus: probe failed for device 5620e0c7-8062-4dce-aeb7-520c7ef76171 (-12) [ 17.009579] hyperv_fb: probe of 5620e0c7-8062-4dce-aeb7-520c7ef76171 failed with error -12 2) Somtimes VM starts with kernel panic Expected results: VM can start without error
This bug exists in the latest mainline kernel.
Issue still occurs on kernel: 4.18.0-369.el8.x86_64 [root@vm-197-97 ~]# dmesg | grep hyperv_fb [ 6.671212] hv_vmbus: registering driver hyperv_fb [ 6.672327] hyperv_fb: Synthvid Version major 3, minor 5 [ 6.672356] hyperv_fb: Screen resolution: 1024x768, Color depth: 32, Frame buffer size: 134217728 [ 6.672360] hyperv_fb: Unable to allocate enough contiguous physical memory on Gen 1 VM. Using MMIO instead. [ 6.672360] hyperv_fb: Resource not available or (0x4000000 < 0x8000000) [ 6.674032] hyperv_fb: No memory for framebuffer [ 6.677325] hyperv_fb: probe of 5620e0c7-8062-4dce-aeb7-520c7ef76171 failed with error -12 [root@vm-197-97 ~]# uname -r 4.18.0-369.el8.x86_64 [root@vm-197-97 ~]#
Please try the fix, upstreamed in fbdev-next: https://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git/commit/?h=for-next&id=c4b4d7047f16a8d138ce76da65faefb7165736f2
(In reply to Saurabh Sengar from comment #11) > Please try the fix, upstreamed in fbdev-next: > https://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git/ > commit/?h=for-next&id=c4b4d7047f16a8d138ce76da65faefb7165736f2 Hi Saurabh, We have tested the above patch, it could fix this issue. Both Gen 1 and Gen 2 VM can start with GUI successfully when set MAX resolution > 3840x4320, e.g. change maximum resolution by “Set-VMVideo RHEL-8.7.0-x86_64-gen1-xx -HorizontalResolution 7680 -VerticalResolution 4320 -ResolutionType Maximum”. Thank you so much. Best Regards, Xuemin
Checked with compose RHEL-8.7.0-20220619.0-x86_64-gen1, now this issue not appear, and GUI login display well. PS C:\WINDOWS\system32> Set-VMVideo RHEL-8.7.0-20220619.0-x86_64-gen1-1948442-A -HorizontalResolution 7680 -VerticalResolution 4320 -ResolutionType Maximum [root@vm-198-218 ~]# dmesg | grep -i error [root@vm-198-218 ~]# cat /etc/default/grub | grep video GRUB_CMDLINE_LINUX="crashkernel=auto resume=/dev/mapper/rhel_vm--198--218-swap rd.lvm.lv=rhel_vm-198-218/root rd.lvm.lv=rhel_vm-198-218/swap rhgb quiet video=hyperv_fb:1920x1080" [root@vm-198-218 ~]# uname -r 4.18.0-402.el8.x86_64 [root@vm-198-218 ~]# [root@vm-198-218 ~]# ls /var/crash/ [root@vm-198-218 ~]#
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: kernel security, bug fix, and enhancement update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2022:7683