Post Atvf6GSj2SsMeT0wuu by dbat@mastodon.gamedev.place
(DIR) More posts by dbat@mastodon.gamedev.place
(DIR) Post #Atvelo9OajzT3KDbkG by wolf480pl@mstdn.io
2025-05-09T20:43:42Z
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What's the name of the mechanism which UEFI uses to pass a splash screen to windows bootloader?
(DIR) Post #Atvf6GSj2SsMeT0wuu by dbat@mastodon.gamedev.place
2025-05-09T20:47:21Z
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@wolf480pl Chance.
(DIR) Post #Atvf8dW0IdqKjCg8w4 by wolf480pl@mstdn.io
2025-05-09T20:47:49Z
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@dbat you mean it just leaves it in the framebuffere and windows doesn't clear it?
(DIR) Post #AtvfDU6uh3cd0YFr7I by dbat@mastodon.gamedev.place
2025-05-09T20:48:40Z
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@wolf480pl lol! Yes!
(DIR) Post #AtvfEk80cqqQyXMpea by wolf480pl@mstdn.io
2025-05-09T20:48:56Z
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@dbat then what's the purpose of the BGRT ACPI table?
(DIR) Post #AtvfGcXXoECC1KCrYm by dbat@mastodon.gamedev.place
2025-05-09T20:49:15Z
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@wolf480pl You might have rumbled me!
(DIR) Post #Atvg12poNWrgtOt5bE by wolf480pl@mstdn.io
2025-05-09T20:57:39Z
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@dbat okay, apparently it uses BGRT in"Setup, Startup Repair, Push-Button Reset, or other experiences"https://learn.microsoft.com/en-us/windows-hardware/drivers/bringup/boot-screen-componentsbut during boot, it just leaves whatever was there in the framebufferinteresting...
(DIR) Post #AtvhFwjzPxGoI4plUO by wolf480pl@mstdn.io
2025-05-09T21:11:31Z
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@nytpu ok somy laptop's UEFI does place the logo inside the BGRT (checked under linux in /sys/firmware/acpi/bgrt)and when I boot from UEFI straight into windows, the logo persistsbut when i boot to grub and then chainloader into bootmgfw.efi, the logo is missingso I'm guessing this is the "just doesn't clobber" case.Are you saying that I can configure windows to show BGRT logo during boot instead? I didn't find anything about that in the article you linked :/
(DIR) Post #AtvhScd5VCmDgHeLr6 by wolf480pl@mstdn.io
2025-05-09T21:13:49Z
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@nytpu based on what I read in the article, it is used by windows in some context *other* than the boot screen
(DIR) Post #AtvhrFTIjvGV67ob6O by wolf480pl@mstdn.io
2025-05-09T21:18:17Z
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@nytpu anyway, now I'm trying to figure out how to make grub not reset the framebuffer when it chainloads another efi application
(DIR) Post #AtviQ29MGFxpuu4cz2 by dbat@mastodon.gamedev.place
2025-05-09T21:24:29Z
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@wolf480pl A person that you might get real info from is @alcinnz Hit them up!
(DIR) Post #AtviuwN5nNP6yLEeOm by alcinnz@floss.social
2025-05-09T21:26:44Z
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@dbat @wolf480pl I'm sorry, I'm not aware of the answer.I might learn it soon if GRUB used it, but I don't think GRUB does!
(DIR) Post #AtviuxIsKXcnrYGnSq by wolf480pl@mstdn.io
2025-05-09T21:30:07Z
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@alcinnz @dbat @nytpu Ok so apparently GRUB clears the menu from the framebuffer when selecting a menuentry, but if anything that happens inside the menuentry draws on the screen, (eg echo "TEST") then that will be left when windows is booting...and I'm guessing the background set by GRUB theme will be drawn behind the gfxterm even after the menu is gone? Let's try that
(DIR) Post #AtvpC6LaYgdWYk68rQ by wolf480pl@mstdn.io
2025-05-09T22:40:30Z
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@alcinnz @dbat @nytpu yup, doingconvert /sys/firmware/acpi/bgrt/image -background none -extent 2560x1600-960-611 /boot/grub/bgrt.pngand then using that as the background did the trick.2560x1600 is my screen res, 960 and 611 are xoffset and yoffset from /sys/firwmare/acpi/bgrt/. They specify where the image should be on the screen, but I had to pad it since grub's background_image command doesn't support offsets.