Linux framebuffer on iMX7

[igiona]

These days I'm playing around with the Framebuffer head of linux.

My embedded machine runs on a iMX7 ARM32, and has a LCD display connected.
I can run and display a QT application using FB, hence the framebuffer seems to be setup correctly.

I can also run my Uno app (sample app from the uno wizard), and the bootup doesn't sound too bad :)

root@b2qt-colibri-imx7:~# FRAMEBUFFER=/dev/fb0 dotnet /mnt/sdcard/uno/TestFrameBuffer.Skia.Linux.FrameBuffer.dll
warn: Uno.Extensions.Storage.FileStorage[0]
      ReadPackageFileAsync - File 'appsettings.keyvaluestorageconfiguration.json' does not exist in package
03-13 14:09:17.988+00:00 W/Uno.Extensions.Storage.FileStorage: ReadPackageFileAsync - File 'appsettings.keyvaluestorageconfiguration.json' does not exist in package
warn: Uno.Extensions.Storage.FileStorage[0]
      ReadPackageFileAsync - File 'appsettings.appconfig.json' does not exist in package
03-13 14:09:18.309+00:00 W/Uno.Extensions.Storage.FileStorage: ReadPackageFileAsync - File 'appsettings.appconfig.json' does not exist in package
warn: Uno.Extensions.Storage.FileStorage[0]
      ReadPackageFileAsync - File 'appsettings.localizationconfiguration.json' does not exist in package
03-13 14:09:18.314+00:00 W/Uno.Extensions.Storage.FileStorage: ReadPackageFileAsync - File 'appsettings.localizationconfiguration.json' does not exist in package
warn: Uno.Extensions.Storage.FileStorage[0]
      ReadPackageFileAsync - File 'appsettings.localizationsettings.json' does not exist in package
03-13 14:09:18.319+00:00 W/Uno.Extensions.Storage.FileStorage: ReadPackageFileAsync - File 'appsettings.localizationsettings.json' does not exist in package
03-13 14:09:18.468+00:00 I/Uno.Extensions.Navigation.Navigators.ContentControlNavigator: NavigateAsync - Starting Navigation - Navigator: ContentControlNavigator Request:
warn: Uno.Extensions.Navigation.Navigators.ContentControlNavigator[0]
      Show - Missing view for navigation path ''
03-13 14:09:18.663+00:00 W/Uno.Extensions.Navigation.Navigators.ContentControlNavigator: Show - Missing view for navigation path ''
03-13 14:09:18.668+00:00 I/Uno.Extensions.Navigation.Navigators.ContentControlNavigator: CreateControlFromType - Creating control of type FrameView

Trouble is, no pixel is displayed on the screen :'(

My FB is set up as follow:

root@b2qt-colibri-imx7:~# fbset

mode "640x480-60"
        # D: 25.176 MHz, H: 31.469 kHz, V: 59.942 Hz
        geometry 640 480 640 480 16
        timings 39721 40 24 32 11 96 2
        accel false
        rgba 5/11,6/5,5/0,0/0
endmode

I tried also to change the screen size to the actual display size, with the same result...

root@b2qt-colibri-imx7:~# fbset

mode "800x480-50"
        # D: 25.176 MHz, H: 26.225 kHz, V: 49.952 Hz
        geometry 800 480 800 480 16
        timings 39721 40 24 32 11 96 2
        accel false
        rgba 8/16,8/8,8/0,0/0
endmode

Has someone already successfully worked with FB on an embedded machine?

[igiona]

Interestingly enough, after I started the Uno app the FB is changes to:

mode "800x480-50"
        # D: 25.176 MHz, H: 26.225 kHz, V: 49.952 Hz
        geometry 800 480 800 480 32
        timings 39721 40 24 32 11 96 2
        accel false
        rgba 8/16,8/8,8/0,0/0
endmode

Is uno doing this?
Is there a way to tell Uno to use 16bpp ?

[igiona]

I also tried to use the app (default app, clean after wizard), with <InvariantGlobalization>true</InvariantGlobalization>.
But it fails at startup:

Unhandled exception. System.Globalization.CultureNotFoundException: Only the invariant culture is supported in globalization-invariant mode. See https://aka.ms/GlobalizationInvariantMode for more information. (Parameter 'name')

Removing true is not an option, because we don’t have the libicu installed.

[jeromelaban]

Interesting error. Would you have an additional stacktrace for this particular message?

[igiona]

This is everything I get on the console:

$ FRAMEBUFFER=/dev/fb0 dotnet /mnt/sdcard/uno/UnoFrameBuffer.dll
Unhandled exception. System.Globalization.CultureNotFoundException: Only the invariant culture is supported in globalization-invariant mode. See https://aka.ms/GlobalizationInvariantMode for more information. (Parameter 'name')
en is an invalid culture identifier.
   at System.Globalization.CultureInfo..ctor(String name, Boolean useUserOverride)
   at System.Globalization.CultureInfo..ctor(String name)
   at Windows.Globalization.ApplicationLanguages.CreateCulture(String cultureId) in /__w/1/s/src/Uno.UWP/Globalization/ApplicationLanguages.cs:line 206
   at Windows.Globalization.ApplicationLanguages.<ApplyCulture>g__setCulture|14_0(String cultureId) in /__w/1/s/src/Uno.UWP/Globalization/ApplicationLanguages.cs:line 98
   at Windows.Globalization.ApplicationLanguages.ApplyCulture() in /__w/1/s/src/Uno.UWP/Globalization/ApplicationLanguages.cs:line 86
   at Microsoft.UI.Xaml.Application..ctor() in /__w/1/s/src/Uno.UI/UI/Xaml/Application.cs:line 95
   at UnoFrameBuffer.App..ctor() in C:\git\Scewo\.NET\UnoFrameBuffer\UnoFrameBuffer\App.xaml.cs:line 10
   at UnoFrameBuffer.Program.<>c.<Main>b__0_0() in C:\git\Scewo\.NET\UnoFrameBuffer\UnoFrameBuffer\Platforms\Desktop\Program.cs:line 10
   at Uno.UI.Runtime.Skia.Linux.FrameBuffer.FrameBufferHost.<InnerInitialize>g__CreateApp|16_8(ApplicationInitializationCallbackParams _)
   at Microsoft.UI.Xaml.Application.StartPartial(ApplicationInitializationCallback callback) in /__w/1/s/src/Uno.UI/UI/Xaml/Application.skia.cs:line 90
   at Microsoft.UI.Xaml.Application.Start(ApplicationInitializationCallback callback) in /__w/1/s/src/Uno.UI/UI/Xaml/Application.cs:line 261
   at Microsoft.UI.Xaml.Application.StartWithArguments(ApplicationInitializationCallback callback) in /__w/1/s/src/Uno.UI/UI/Xaml/Application.skia.cs:line 79
   at Uno.UI.Runtime.Skia.Linux.FrameBuffer.FrameBufferHost.InnerInitialize()
   at Uno.Helpers.EventLoop.Run() in /__w/1/s/src/Uno.UWP/Helpers/EventLoop.cs:line 153
   at System.Threading.Thread.StartCallback()
Fatal error. Internal CLR error. (0x80131506)
   at System.Globalization.CultureInfo..ctor(System.String, Boolean)
   at System.Globalization.CultureInfo..ctor(System.String)
   at Windows.Globalization.ApplicationLanguages.CreateCulture(System.String)
   at Windows.Globalization.ApplicationLanguages.<ApplyCulture>g__setCulture|14_0(System.String)
   at Windows.Globalization.ApplicationLanguages.ApplyCulture()
   at Microsoft.UI.Xaml.Application..ctor()
   at UnoFrameBuffer.App..ctor()
   at UnoFrameBuffer.Program+<>c.<Main>b__0_0()
   at Uno.UI.Runtime.Skia.Linux.FrameBuffer.FrameBufferHost.<InnerInitialize>g__CreateApp|16_8(Microsoft.UI.Xaml.ApplicationInitializationCallbackParams)
   at Microsoft.UI.Xaml.Application.StartPartial(Microsoft.UI.Xaml.ApplicationInitializationCallback)
   at Microsoft.UI.Xaml.Application.Start(Microsoft.UI.Xaml.ApplicationInitializationCallback)
   at Microsoft.UI.Xaml.Application.StartWithArguments(Microsoft.UI.Xaml.ApplicationInitializationCallback)
   at Uno.UI.Runtime.Skia.Linux.FrameBuffer.FrameBufferHost.InnerInitialize()
   at Uno.Helpers.EventLoop.Run()
   at System.Threading.Thread.StartCallback()
Aborted

[jeromelaban]

Thanks, this is useful.

[jeromelaban]

Let's track in #18283