After some idle time guest window resizes itself to 800x600 on keyboard input

[Elvinas]

I am facing strange problem after update to 5.2.6. If VirtualBox guest is left idle'ing for some time (somewhere 20+ minutes) then after keyboard input, guest window is shrinked to 800x600. If I do not press any key on keyboard, but control guest VM content with mouse, nothing happens. Bus on a first keypress, window is suddenly reduced to 800x600. Also on guest boot, window is not scaled to selected guest resolution. Guest display gets obviously larger that window size, but there are no scroll bars.

Clicking on View -> Adjust Window size does nothing. I need manually resize guest window each time. Which is quite annoying, plus results in desktop environment cresh some times (but thats another story).

I have tried to set File -> Preferences -> Display to Automatic, Hint and none. I have tried to check/uncheck "View -> Auto resize Guest display". No effect. Also. If "Auto resize Guest display" is not checked, after window size is reduced, viewport size is not changed on window resize. Even if I stretch window, guest viewport size remains the same and just gray window border is increased.

Any ideas how to prevent window resizing on keypress.

I see the following entries in the VM log, when window is resized(02:57:05).

00:33:57.642743 Display::handleDisplayResize: uScreenId=0 pvVRAM=000000000e9e5000 w=1880 h=1043 bpp=32 cbLine=0x1D60 flags=0x1
00:33:57.642791 GUI: UIFrameBufferPrivate::NotifyChange: Screen=0, Origin=0x0, Size=1880x1043, Sending to async-handler
00:33:57.754593 GUI: UIMachineView::storeGuestSizeHint: Storing guest-screen size-hint for screen 0 as 1792x1008
00:33:57.810922 GUI: UIMachineView::sltHandleNotifyChange: Screen=0, Size=1880x1043
00:33:57.810958 GUI: UIFrameBufferPrivate::handleNotifyChange: Size=1880x1043
00:33:57.811019 GUI: UIFrameBufferPrivate::performResize: Size=1880x1043, Directly using source bitmap content
00:33:57.824286 GUI: UIMachineView::storeGuestSizeHint: Storing guest-screen size-hint for screen 0 as 1880x1043
00:33:57.922942 GUI: UIMediumEnumerator: Medium-enumeration finished!
00:56:09.004521 Audio: Host audio device configuration has changed
00:56:09.078921 Audio: Host audio device configuration has changed
01:59:56.640272 Audio: Host audio device configuration has changed
01:59:56.798130 Audio: Host audio device configuration has changed
02:57:05.132230 VBVA: InfoScreen: [0] @0,0 800x600, line 0xc80, BPP 32, flags 0x1
02:57:05.132366 Display::handleDisplayResize: uScreenId=0 pvVRAM=000000000e810000 w=800 h=600 bpp=32 cbLine=0xC80 flags=0x1
02:57:05.132435 GUI: UIFrameBufferPrivate::NotifyChange: Screen=0, Origin=0x0, Size=800x600, Sending to async-handler
02:57:05.133211 GUI: UIMachineView::sltHandleNotifyChange: Screen=0, Size=800x600
02:57:05.133232 GUI: UIFrameBufferPrivate::handleNotifyChange: Size=800x600
02:57:05.133259 GUI: UIFrameBufferPrivate::performResize: Size=800x600, Directly using source bitmap content
02:57:05.256045 GUI: UIMachineView::storeGuestSizeHint: Storing guest-screen size-hint for screen 0 as 800x600
02:57:05.324346 GUI: UIMediumEnumerator: Medium-enumeration finished!

Host: Windows 10
guest: Linux Mint 18.3 with 3D acceleration enabled.
Vbox and Guest tools: 5.2.6

[mpack]

Guest windows don't resize themselves. They change size when you tell it, or when the guest OS tells it.

Btw, partial logs are nearly useless for diagnostics. Always zip and attach the entire log.

[Elvinas]

Guest windows don't resize themselves. They change size when you tell it, or when the guest OS tells it.

I understand that. It just that there should not be any command to change size neither from me or guest OS. Resolution is not changed in Guest OS, when guest OS is left idle'ing, while I am browsing internet or writing emails. However when I return focus to VirtualBox and press any key, window is resized ("resizes itself"). Also after such resize, guest kind of "ignores" mouse inputs until window is resized manually and proper guest resolution to window viewport size mapping is done. In quotes, as guest still reacts to mouse clicks, but they are not registered where I would expect them.

Resized window after input.

vbox-resized.JPG (50.85 KiB) Viewed 947 times

Additional check shows that I am still using 5.2.4 guest tools. I have deliberately downgraded due to inability to use 5.2.6 at all. With 5.2.6 guest simply crashed on boot on first upgrade. After I have tried today to upgrade to 5.2.6 again, Linux Mint warned me about working in software rendering mode and then went into endless loop of sizing and resizing window between 800x600 to configured 1920x1080.

With 5.2.6 I saw the following errors in Xorg.log (vboxvideo module was loaded)
(EE) /dev/dri/card0 failed to set DRM interface version 1.4 Permission denied


Adding zipped logs.

This is not the only issues with 5.2. I am still experiencing pixelation as I have defined in ticket: #16664

Virtualbox still complains about NVidia driver signature, although Windows10 says it does have valid one (and I have tried various drivers from MS, Dell and Nvidia tself) and according to log, Intel driver is used for 3D rendering, not NVidia so not sure why it should cause any issues for #16664 .
Ticket #13882

PS: "You must be a member for 1 days and have 1 posts before you can post urls". Forum parser complained about xorg log content

[socratis]

With 5.2.6 guest simply crashed on boot on first upgrade.

You need to update the GAs to something newer than 5.2.6. See the "Important" paragraph in the Downloads section, or try the latest test builds, especially with all the Spectre/Meltdown patches coming in from all sides.