feat: vblank IRQ and double-buffered page flip for Intel GPU

Add tear-free scanout to the Intel GPU driver: a second kernel-allocated
scanout buffer, DSPASURF flips latched at vblank, and a vblank interrupt
delivered over MSI (Gen 11+ master/display/pipe IRQ chain) with a
monotonic vblank counter and WaitVblank().

Expose it as SYS_FBFLIP (150): index selects the front buffer, -1
queries support, flags bit0 waits for the flip to latch. fb_map() now
maps buffer 1 right after buffer 0 when flipping is available, and
gui::Framebuffer draws to the off-screen buffer and flips with vsync,
falling back to the direct copy when unsupported.

Scanout is restored to buffer 0 when the flip-owning process exits and
on panic, so the terminal and panic box never land on the invisible
buffer.

Co-Authored-By: Claude Fable 5 <[email protected]>

This commit is contained in:

daniel

2026-07-13 21:53:06 +02:00

co-authored by

Claude Fable 5

parent 500020ce47

commit 182520a585

14 changed files with 549 additions and 3 deletions

									
										programs/include/libc/montauk.h
									
		+1
		
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				@@ -173,6 +173,7 @@ extern "C" {

				#define MTK_SYS_SDR_SETPARAM       147

				#define MTK_SYS_SDR_GETPARAM       148

				#define MTK_SYS_POWERINFO          149

				#define MTK_SYS_FBFLIP             150

				/* @SYSCALLS-END */

				#define MTK_SOCK_TCP 1