ebook viewer crashing on launch (7.5.1)

[KaizaCorp]

After updating to the most recent version (7.5.1 currently) I now have the issue where using the Calibre ebook viewer crashes when loading any ebook. I ran it with the debug flag and got the following output:

QPA platform: windows
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 81.55183946488295 x 81.64285714285714
ApplicationPaletteChange event ignored
Using calibre Qt style: True
ApplicationPaletteChange event received
QWindowsGLContext::makeCurrent: wglMakeCurrent() failed (The handle is invalid.)
QRhiGles2: Failed to make context current. Expect bad things to happen.
Failed to create QRhi for QBackingStoreRhiSupport
Failed to make context current.
Failed to make context current.
Failed to make context current.
[0.000] Load of book started
[0.016] prepared emitted
[0.047] webview loading requested

I've had this issue after updating in the past, but restarting always seemed to fix it. However this time that doesn't seem to be a solution. Has anyone encountered this? Perhaps a library I need to reinstall? Downgrade a graphics driver?

Thanks!

[kovidgoyal]

The problem is here
QWindowsGLContext::makeCurrent: wglMakeCurrent() failed (The handle is invalid.)

Defintely a GPU driver issue. Try rolling them back if they were recently updated or try updating them if there is an update available. You can also try using software rendering as described in https://doc.qt.io/qt-6/qtwebengine-debugging.html

[KaizaCorp]

On the latest AMD driver which lines up with when the issue started.

I've tried using the --disable-gpu flag with ebook-viewer.exe to force software rendering but no luck there (as there doesn't seem to be an equivalent option with calibre-debug.exe ?) I tried setting an environment variable (in Windows 10) but that hasn't had any effect either. Is there any other method of forcing software rendering?

Thank you for your time!

[kovidgoyal]

the env var is the only method, you dont specify it ont he command line, you set the env var. Possibly reboot to make sure the env var is set everywhere.

[KaizaCorp]

Ah I had an extra underscore in the environment variable. Thank you! I ran it again (calibre-debug.exe --viewer) and the ebook window shows up now, but the contents of the window are all blank / not visible.

Here is the debug output:

QPA platform: windows
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 81.55183946488295 x 81.64285714285714
ApplicationPaletteChange event ignored
Using calibre Qt style: True
ApplicationPaletteChange event received
QWindowsGLContext::makeCurrent: wglMakeCurrent() failed (The operation completed successfully.)
QRhiGles2: Failed to make context current. Expect bad things to happen.
Failed to create QRhi for QBackingStoreRhiSupport
[0.000] Load of book started
[0.015] prepared emitted
[0.078] webview loading requested
[0.281] bridge ready
[0.390] iframe ready
[0.453] loading finished

If I mouse over the window I can see the cursor change as it goes over text, and can copy/paste text from the ebook, however it's all just not visible. It's the same when opening ebooks directly from Calibre as well.

[theducks]

Sounds like you have white text on white background (or Black on Black)
try a color override (using preferences)

[KaizaCorp]

Originally Posted by theducks

Sounds like you have white text on white background (or Black on Black)
try a color override (using preferences)

I last had it set to black text on sepia background. Let me clarify, no interface elements are visible, the window is completely blank. If I resize the window from smaller to larger, it becomes black. Some kind of rendering issue or elements not being drawn?

EDIT:

Okay, interestingly I can see the text and interact with the ebook if the window is started *not* maximized (however the text is not rendered properly, kind of jagged). If I maxmize it, everything goes blank again and I have to relaunch to be able to see anything. If I try to fullscreen it, instead of going blank the content of the window stays as is, but I can no longer see page changes or UI elements.

EDIT2:

Even stranger, if I take the non-maximized window with the jagged fonts (for both UI and ebook text) and drag it to the top of the screen (which is an action that would maximize the window) but *do not* let go of the mouse button and instead drag it down and away from that zone, the text is rendered with jagged edges.

So to recap:

Software rendering works, but:

- the window needs to be not full size on launch
- the window needs to be "refreshed" by moving it to the top area to maximize and back down again
- maximizing the window will prevent any changes from being rendered
- starting the window maximized only shows a blank window

EDIT3:

This behaviour is persisting even without the "--disable-gpu" environment variable on QTWEBENGINE_CHROMIUM_FLAGS, so still to do with this gpu driver version as I can't seem to get the software rendering to work.

[JSWolf]

Are you on a laptop with dual video cards? If so, set calibre to use the other video card. This solution has helped others.

[KaizaCorp]

Originally Posted by JSWolf

Are you on a laptop with dual video cards? If so, set calibre to use the other video card. This solution has helped others.

No, I'm on a desktop with an AMD graphics card (RX 6750 XT) and no on-board graphics (AMD Ryzen 5 5600).

[KaizaCorp]

Couldn't get the software rendering to work, but I downgraded my graphics drivers to AMD Adrenalin 23.12.1 and it's working normally.

[KaizaCorp]

Upgraded Calibre to 7.8 (on the same AMD Adrenalin version as before 23.12.1) and getting this ebook viewer rendering issue once more.

Window shows up but only renders white when maximized or in windowed mode but larger than the screen / out of bounds. If the window Mouse pointer changes when over different elements and text can be copied, but only renders as white.

Ebook contents only visible if launched with the window strictly smaller than the size of the screen in windowed mode. Text is not rendered properly and needs to be dragged against the top of the screen (some kind of pre-maximization step?) and then dragged backed down to not render it as white. Once it gets rendered white it won't change back and needs to be relaunched.

Here's the output when running from the command line:

QPA platform: windows
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 81.55183946488295 x 81.64285714285714
ApplicationPaletteChange event ignored
Using calibre Qt style: True
ApplicationPaletteChange event received
QWindowsGLContext::makeCurrent: wglMakeCurrent() failed (The handle is invalid.)
QRhiGles2: Failed to make context current. Expect bad things to happen.
Failed to create QRhi for QBackingStoreRhiSupport
Failed to make context current.
Failed to make context current.
QWindowsGLContext::makeCurrent: wglMakeCurrent() failed (The handle is invalid.)
QRhiGles2: Failed to make context current. Expect bad things to happen.
Failed to create QRhi for QBackingStoreRhiSupport
QQuickWidget: Failed to get a QRhi from the top-level widget's window
QQuickWidget::resizeEvent() no QRhi
Failed to make context current.
Failed to make context current.
QWindowsGLContext::makeCurrent: wglMakeCurrent() failed (The handle is invalid.)
QRhiGles2: Failed to make context current. Expect bad things to happen.
Failed to create QRhi for QBackingStoreRhiSupport
QQuickWidget: Failed to get a QRhi from the top-level widget's window
QQuickWidget: Attempted to render scene with no rhi
[0.000] Load of book started
[0.015] prepared emitted
[0.047] webview loading requested
[0.375] bridge ready
QQuickWidget: Attempted to render scene with no rhi
[0.500] iframe ready
[0.547] loading finished

EDIT:

Back to working maximized after a restart. Still requires window to be dragged and "bumped" against the top to fix font aliasing though.